Undertale
Hints and Tips:
---------------
Submitted by: David K.
-= Choose the Route before You Start Killing =-
Undertale remembers more than the room you are standing in. Killing even one ordinary
monster gives EXP and blocks True Pacifist until you reload a save from before that
kill or RESET the run. Genocide is stricter: every area quota and required encounter
must be cleared before the route advances. Decide whether you want Neutral, True
Pacifist or Genocide before turning random encounters into permanent route decisions.
-= True Pacifist Still Starts with a Neutral Completion =-
A first-time True Pacifist run can stay at LV 1 from the beginning, but the final
Pacifist quest line does not open until a Neutral ending has been completed. After
Omega Flowey, reload the same SAVE instead of starting over. If Papyrus and Undyne
were already befriended and no EXP was gained, backtrack for Undyne's Letter,
complete the Alphys date and enter the True Lab.
-= Protect the Three Friendship Gates =-
* Papyrus -> spare him, then visit his house in Snowdin for the date/hangout.
* Undyne -> flee her battle, reach Hotland, pour water on her after she collapses,
then return to her Waterfall house with Papyrus while still at 0 EXP.
* Alphys -> after a Neutral completion, deliver Undyne's Letter to the Lab, complete
the date, then return when Papyrus calls and enter the former bathroom/True Lab.
Missing the water step is especially costly because Undyne cannot complete the
friendship event afterward on that run.
-= Pacifist Means No EXP, Not Never Pressing FIGHT =-
True Pacifist requires 0 EXP and LV 1. You may use FIGHT without ruining the route if
the target survives and the encounter still ends nonlethally, but there is little
reason to risk an accidental kill. Use ACT, MERCY and Flee as the normal route.
Asgore and Flowey do not create saved EXP after the first Neutral finale.
-= Genocide Is an Area Quota Route =-
Genocide is not simply high LV. You must exhaust the random-encounter quota in each
area and also kill the route-required named encounters. SAVE points eventually
replace normal flavor text with a remaining-kill count and then `Determination.` when
the local quota is empty.
* Ruins -> 20 random kills before leaving the area; kill Toriel.
* Snowdin -> 16 random kills; Snowdrake is mandatory, and Doggo, Dogamy/Dogaressa and
Greater Dog must also die. Kill Lesser Dog if you encounter it. Kill Papyrus.
* Waterfall -> 18 random kills; kill Shyren and Glad Dummy, attack Monster Kid and
defeat Undyne the Undying.
* Hotland + CORE -> 40 combined random kills; kill the Royal Guards and Muffet, then
destroy Mettaton NEO.
-= RESET and True Reset Do Different Jobs =-
A normal RESET starts the story over but does not erase every piece of persistent
memory. True Reset becomes available after the True Pacifist ending and clears much
more route memory. Neither operation removes the post-Genocide consequence flag once
the world has been restored through the SOUL deal; that PC-specific state is covered
under Save Editing.
-= Use the Alternate Keyboard Inputs When Z X C Are Awkward =-
On Windows, Enter also confirms like Z, Shift cancels like X and Ctrl opens the menu
like C. The arrow keys move. F4 toggles fullscreen. These are useful when a keyboard
layout or remapping makes the letter keys inconvenient.
-= Use Joystick Config before External Remapping =-
On current Windows builds, start UNDERTALE with the intended controller connected,
open Settings and choose JOYSTICK CONFIG. The menu can remap Confirm, Cancel and
Menu, switch between analog/POV direction input, adjust analog sensitivity and run a
control test. If two controller-class devices conflict, disconnect the unused one and
relaunch before adding Steam Input or another mapping layer.
-= Alphys's Phone Gives You Two Ten-Slot Boxes =-
The carried inventory holds eight items. Every physical Dimensional Box accesses Box
A, which stores ten more. On Neutral/True Pacifist, Alphys upgrades the Cell Phone in
Hotland so it can reach both Box A and a separate ten-slot Box B from almost
anywhere. That gives 28 usable item slots for long trips and makes the Cloudy-Glasses
money loop much faster. Genocide does not receive the phone upgrade; extra physical
Box A locations appear instead.
-= Buy One Ruins Spider Item for Muffet =-
The Spider Donut and Spider Cider are cheap in the Ruins and become a major shortcut
much later. Using either during the Muffet battle proves that you supported the
spiders and ends the fight after a short dialogue sequence. The Hotland spider-sale
prices are deliberately enormous, so carrying one early is the efficient route.
-= Keep the Butterscotch Pie for Asgore =-
The pie is a full heal and also weakens Asgore when used during his battle, lowering
his attack and defense. It is one of the most valuable single inventory items in a
blind first run, so avoid consuming it for routine healing unless you genuinely need
it.
-= Burnt Pan Turns Every Healing Item into a Better One =-
The Burnt Pan gives +10 AT and adds 4 HP to healing items while equipped. That bonus
matters even on nonviolent routes where its attack stat does not. Pair it with strong
late-game food when a boss is beating you through attrition.
-= Cloudy Glasses and Torn Notebook Buy More Invulnerability Time =-
Gerson sells both items in Waterfall. Their raw stats are modest, but each increases
post-hit invulnerability time. The pair is therefore useful in difficult bullet
patterns, especially Undyne the Undying and Sans, where surviving repeated contact is
more valuable than ordinary defense alone.
-= Temmie Armor Is the Built-In Difficulty Valve =-
Pay 1000G for Temmie College, then Temmie Armor becomes purchasable. Its starting
price is 9999G and falls as you die, bottoming out at 750G after enough deaths. It
gives strong defense, extra attack, longer invulnerability and passive healing. The
armor is unavailable on Genocide, where Tem Shop evacuates.
Routes and Endings:
-------------------
-= Neutral Is the First Main Ending Family =-
Any run that reaches Asgore without satisfying True Pacifist or Genocide ends in the
Neutral family. Asgore and Omega Flowey are the unique finale. The post-credits phone
call changes according to which major characters and ordinary monsters survived, so
Neutral is a family of outcomes rather than one fixed epilogue.
-= Major Neutral Ending Map =-
* Toriel spared -> Toriel can rule. At LV 1 with Papyrus and Undyne befriended, this
is the peaceful Family/Flawed-Pacifist variant; other kill/friendship states create
Betrayed Undyne or Exiled Queen variants.
* Toriel dead, Undyne alive -> Undyne becomes ruler.
* Toriel and Undyne dead, Mettaton alive -> Mettaton becomes ruler.
* Toriel, Undyne and Mettaton dead, Papyrus alive -> Papyrus becomes ruler.
* Toriel, Papyrus, Undyne and Mettaton dead while all other ordinary monsters survive
-> Dog ending.
* All four major figures dead plus at least one ordinary monster dead -> leaderless
ending.
* Follow Genocide through Waterfall, then abort it in Hotland/CORE -> Alphys
near-Genocide ending.
The names above are community labels, not in-game menu names. Many phone-call
subvariants exist, but these are the major outcome families that change who leads the
Underground or how the survivors respond.
-= True Pacifist Route - Minimum Complete Plan =-
1. Finish a Neutral ending once while keeping 0 EXP if you want to continue directly
from that save.
2. Spare Papyrus and complete the date/hangout at his Snowdin house.
3. During Undyne's chase battle, flee whenever the SOUL turns red. After reaching
Hotland, pour water on the collapsed Undyne.
4. Return to Undyne's Waterfall house with Papyrus and complete the cooking/hangout
event while still at 0 EXP.
5. Spare Mettaton EX and finish the first Neutral finale against Asgore and Omega
Flowey.
6. Reload the SAVE, backtrack from CORE/MTT Resort until Undyne calls, collect her
Letter outside Papyrus's house and deliver it to Alphys.
7. Complete the Alphys date. After Papyrus calls, return to the Lab and enter the
former bathroom to reach the True Lab.
8. Find and place all four True Lab keys, restore the generator and ride the elevator
back to New Home. From this point the True Pacifist finale is locked in.
-= True Lab - Four-Key Route =-
1. From the power-room lobby, take the left path and turn on the three sinks. Spare
the Memoryheads to receive the Red Key, then use it on the red slot/door.
2. Behind the red door, search the middle-right bed in the bedroom for the Yellow
Key. Its slot is in the VHS room beside the DT Extraction Machine.
3. From the bedroom, take the corridor toward the DT Extraction Machine and open the
bathtub curtain to obtain the Green Key. Its slot is beyond the refrigerator room.
4. Turn on the fan so the refrigerator room becomes readable, then inspect the fifth
fridge and spare Snowdrake's Mother to receive the Blue Key. The blue slot is
reached from the bedroom's eastern mirror corridor after Reaper Bird.
5. After all four keys are inserted, return to the central power-room door, start the
generator and go back to the elevator.
-= Genocide Route - Do Not Leave an Area Early =-
The safest procedure is to empty each random-encounter quota before fighting the area
boss. Walk in encounter-enabled rooms until the game gives `But nobody came.` and the
SAVE points show Determination, then verify the required named encounters were also
killed. Leaving an area or sparing a required target can permanently collapse the run
into Neutral unless you reload an earlier save.
-= Post-Genocide World Restoration Has a Permanent Price =-
After the Genocide ending destroys the world, relaunching leads to an empty screen.
Wait about ten minutes for the fallen human to offer restoration in exchange for the
protagonist's SOUL. Accepting restores playability, but later True Pacifist and
Genocide endings are altered. Neutral endings are not changed by that flag.
-= Backtrack to Asriel before Leaving the True Pacifist Epilogue =-
After the Asriel battle, the barrier is gone and you may walk back through the
Underground before taking the final exit. Return all the way to the first
golden-flower bed in the Ruins for a missable conversation with Asriel. Once you
leave for the Surface, watch the credits and later reload, that version of Asriel is
gone.
-= Hard Mode Is Only the Ruins =-
Name the fallen human `Frisk` to start Hard Mode. It swaps in harder Ruins encounters
and changes some text/items, but it deliberately ends after the Toriel sequence. It
is an unfinished joke mode, not a full fourth campaign. Naming the fallen human
`Gaster` instead kicks you back to the opening rather than starting a route.
Combat and Mercy:
-----------------
-= Blue and Orange Attacks Have Opposite Rules =-
Blue attacks punish movement: stay still while they pass through the SOUL. Orange
attacks punish standing still: keep moving through them. This color rule is reused
across several battles and is more important than memorizing one specific pattern.
-= Know What Each SOUL Color Changes =-
* Red -> normal free movement inside the battle box.
* Green -> shield mode; press the direction of the incoming spear/arrows.
* Blue -> gravity/jump rules; treat the bottom of the box as ground unless the attack
changes gravity.
* Purple -> movement is constrained to web lines; switch lines instead of trying to
move freely.
* Yellow -> shooter mode; use the confirm/action button to fire when the battle calls
for it.
-= MERCY Usually Requires a State, Not Low HP =-
Many monsters become spareable only after a specific ACT sequence or attack-pattern
condition. Watch the name color and battle text instead of assuming low HP is the
universal trigger. Bosses such as Undyne and Asgore deliberately break the normal
spare flow and need route-specific solutions.
-= Bandage Turns Ordinary Flee Attempts into a Guarantee =-
Where MERCY -> Flee is allowed, the normal success chance starts at 50% and rises by
10 percentage points each turn. Wearing the Bandage makes ordinary fleeing guaranteed
except in Hard Mode. Bosses and scripted encounters can still disable Flee entirely,
so the Bandage is an escape tool for normal encounters, not a boss bypass.
-= Do Not Grind Levels on a Pacifist Run =-
EXP is a route flag, not a harmless stat upgrade. A stronger character obtained by
killing monsters is no longer eligible for True Pacifist. If survival is the problem,
solve it with equipment, healing, ACT knowledge, Temmie Armor or practice instead of
combat grinding.
-= Serious Mode Changes Some Healing Items =-
During the hardest late-game battles, several foods become stronger or faster to use.
Instant Noodles are the standout: they heal 90 HP in Serious Mode but are poor
normal-battle food. Save them for the fights that actually trigger Serious Mode
rather than judging them only by their ordinary value.
-= Mettaton EX Is a Ratings Battle =-
The peaceful win condition is audience rating, not reducing him to zero HP. Reach
10,000 ratings after his arms and legs are gone, or 12,000 while they remain. Pose,
answer prompts, shoot marked targets in yellow-SOUL phases and use rating-friendly
items such as Legendary Hero to push the meter instead of treating him like a normal
damage race.
Items and GOLD:
---------------
-= Cloudy Glasses Are the Fast Reliable GOLD Loop =-
Buy Cloudy Glasses from Gerson in Waterfall for 30G and sell them to Tem Shop for
50G. Each pair nets 20G. With both dimensional boxes available, a large batch can be
moved and sold repeatedly, making this one of the fastest normal-money loops for
Temmie College and Temmie Armor without glitches.
-= Dog Residue Can Refill Its Own Farming Inventory =-
After the Waterfall piano room opens, the artifact room gives Dog Residue. Using one
fills empty inventory slots with more Dog Residue and Dog Salad. Sell the extras to
Tem Shop, but always keep at least one Residue so the loop can reproduce itself. Dog
Salad has random healing, so treat it as farm by-product rather than dependable boss
food.
-= Carry the Snowman Piece for Its Story Payoff =-
The Snowman Piece heals 45 HP, but carrying it to the ending produces special
dialogue. If you eat or discard the first piece you can obtain one replacement; there
is no endless supply. Keep at least one if you care about the Snowman outcome rather
than short-term healing.
-= Late-Game Healing Priorities =-
* Butterscotch Pie -> full heal plus Asgore debuff; best saved for Asgore unless
another boss truly demands it.
* Instant Noodles -> 90 HP in Serious Mode; excellent emergency food for the hardest
route bosses.
* Legendary Hero -> heals 40 HP and increases attack temporarily; also grants a large
Mettaton rating bonus.
* Burnt Pan equipped -> every healing item restores 4 extra HP.
-= Three More Late-Game Items Worth Knowing =-
* Face Steak -> heals 60 HP; buy the one-time Steak in the Shape of Mettaton's Face
from Burgerpants for 500G.
* Hush Puppy -> heals 65 HP; give a Hot Dog to the dog behind the rightmost MTT
Resort hotel door. It can also end the Endogeny encounter immediately for story
progress.
* Sea Tea -> heals 10 HP and raises SOUL movement speed for the rest of the
encounter. The speed increase can stack several times, but Muffet's web ignores it.
-= Keep the Stick for Its Hidden Battle Uses =-
The starting Stick is not consumed when used in battle. It immediately makes dog
enemies spareable, including Endogeny; makes Madjick spareable; and gives a large
one-time Ratings boost against Mettaton EX. If you have storage space, keeping the
Stick has more long-term utility than its zero attack bonus suggests.
-= Two Small Minigames Have Useful GOLD Rewards =-
Thundersnail costs 10G at Napstablook's snail farm. For the profitable result,
encourage the yellow snail seven times near the start, waiting for each exclamation
mark to disappear; a narrow second-place loss pays 30G, for a net 20G. In Snowdin's
Ball Game, getting the snowball into the hole within six seconds pays 50G the first
time; later red-flag results on that SAVE pay 10G. The Ball Game disappears after
Snowdin's Genocide kill counter is exhausted.
-= The Mysterious Door Is a Completion Reward, Not a Story Gate =-
During the True Pacifist credits, dodge every Kickstarter backer name. Succeeding
unlocks the Mysterious Door in Snowdin on later access. The room behind it is
optional and not required for any ending, so a missed credits run does not invalidate
True Pacifist.
Cheat Mods:
-----------
-= Enable the Retail Debug Functions with UndertaleModTool =-
The debug functions still exist in the current 1.08 data, but the old fixed hex
offset from early guides is build-specific. A safer current route is
UndertaleModTool: back up `data.win` and the save folder, open `data.win`, run the
bundled UTDR `Debug.csx` script, enable debug mode and save the modified data.
Restore the original `data.win` or verify game files to return to stock.
-= High-Value Debug Hotkeys =-
* G -> open a Dimensional Box; in a shop, G adds 5000G.
* S -> open SAVE dialogue; L -> load the current SAVE immediately.
* Backspace -> move faster while held.
* Insert / Delete -> next / previous room in the internal room list.
* F7 -> add 500G; F10 -> toggle wall collision; F12 -> restart the room.
* F3 -> create `system_information_962`. This deliberately creates the post-Genocide
erased-world marker; do not press it on a save you care about.
Debug warps and state keys can create combinations that normal play never produces.
Keep them on an expendable copy and do not use them as ordinary route fixes.
Save Editing:
-------------
-= Back Up the Whole UNDERTALE Folder before Editing =-
Windows save data lives in `%LOCALAPPDATA%\UNDERTALE`. Close the game first and copy
the entire folder somewhere outside Local AppData. Undertale stores route memory
across multiple files, so copying only the visible manual save can leave persistent
route flags behind.
-= Use the Web Save Editor for Structured Changes =-
Cofeiini's Undertale Save Editor still provides a Web Edition for the original PC
release. It can edit file0 and undertale.ini without relying on a fixed executable
offset. Upload copies only, keep the untouched UNDERTALE folder outside the live save
directory and test one change at a time. The older desktop executable is deprecated;
use the Web Edition when you want its current field descriptions.
-= High-Value file0 Line Map =-
* Line 1 -> fallen-human name.
* Line 2 -> LV; 3 -> current HP; 4 -> maximum HP.
* Line 5 -> base AT; 6 -> weapon AT bonus; 7 -> base DF; 8 -> armor DF bonus.
* Line 10 -> EXP.
* Line 11 -> GOLD.
* Line 12 -> kill count/state counter.
* Lines 13/15/17/19/21/23/25/27 -> the eight carried inventory item IDs.
* Line 29 -> equipped weapon ID; line 30 -> equipped armor ID.
* Line 31 -> major plot/event value. Treat this as high risk; nearby flags may not
agree.
* Line 36 -> current `fun` value.
* Lines 331-340 -> Dimensional Box A; lines 343-352 -> Dimensional Box B.
* Line 548 -> saved room ID. A bad room/state combination can trigger Dogcheck.
-= Simple GOLD Edit =-
1. Close UNDERTALE and back up the complete save folder.
2. Open `file0` in a plain-text editor and replace line 11 with the GOLD amount you
want. `9999` is enough for every ordinary purchase and avoids an unnecessary
extreme value.
3. Save without adding or deleting lines, relaunch once and verify the amount before
making any second edit.
-= Retail Item IDs for Inventory Edits =-
Put an item ID on one of the eight inventory lines above. These are normal retail
items; avoid undocumented/unused IDs unless you are deliberately testing broken
state.
* 3 Stick; 4 Bandage; 7 Spider Donut; 10 Spider Cider; 11 Butterscotch Pie.
* 16 Snowman Piece; 22 Temmie Flakes; 23 Abandoned Quiche; 26 Punch Card.
* 27 Annoying Dog; 28 Dog Salad; 29-34 Dog Residue variants.
* 35 Astronaut Food; 36 Instant Noodles; 37 Crab Apple; 38 Hot Dog...?; 39 Hot Cat.
* 40 Glamburger; 41 Sea Tea; 42 Starfait; 43 Legendary Hero.
* 44 Cloudy Glasses; 45 Torn Notebook; 46 Stained Apron; 47 Burnt Pan.
* 48 Cowboy Hat; 49 Empty Gun; 50 Heart Locket; 51 Worn Dagger.
* 52 Real Knife; 53 The Locket; 54 Bad Memory; 55 Dream.
* 56 Undyne's Letter; 57 Undyne's Letter EX; 58 Popato Chisps; 59 Junk Food.
* 60 Mystery Key; 61 Face Steak; 62 Hush Puppy; 63 Snail Pie; 64 Temmie Armor.
-= Know the Main Save Files before Touching Them =-
* `file0` -> main manual-save data, including room, stats, inventory and many route
flags.
* `file9` -> autosave-style current-state copy used for some reload/recovery
behavior.
* `file8` -> Omega Flowey persistence/progression data.
* `undertale.ini` -> configuration plus values used by several persistent events.
Edit only after making a backup. Invalid room or state combinations can load into the
Annoying Dog error screen instead of repairing themselves.
-= Change the Fallen-Human Name Only with Matching Save State =-
The name appears in `file0` and related configuration state. Editing one copy while
leaving another mismatched can be overwritten by load/reset behavior. If you
deliberately rename a save, back up first and keep the related stored name consistent
rather than changing a single visible line and assuming the job is finished.
-= Current Versions Use lowercase fun =-
The current event variable is `fun`, not the old public-Cheatbook instruction that
tells players to change a capitalized `Fun`. The value can be edited on line 36 of
`file0` and in the `[General]` section of `undertale.ini`; several rare events
require the two values to agree. Use a value from 1 to 100, then load an appropriate
room/state for that event.
-= Steam Genocide Flags Need Special Handling =-
After world erasure, PC creates `system_information_962`; after accepting the SOUL
deal it becomes `system_information_963`. On Steam, simply deleting 962 locally is
not reliable because Steam can restore that acquisition from its cloud state even
when ordinary synchronization appears disabled. The least destructive supported
community procedure is to wait ten minutes, accept the SOUL deal so 962 converts to
963, then close the game and delete or rename 963 only if you deliberately want to
remove the post-Genocide consequence. Keep an untouched backup first.
-= GOG Galaxy Can Also Restore Deleted Route State =-
The GOG build is DRM-free and works without Galaxy, but Galaxy cloud saving can
restore files you intentionally removed. If you are performing a deliberate local
reset or consequence edit on the GOG version, disable Galaxy cloud saving first, make
the change with the game closed and verify the result before re-enabling sync.
-= Do Not Use the Old Public Debug Hex Offset =-
Older Cheatbook material describes enabling debug mode by hex-editing one fixed
executable offset. That instruction belongs to an older binary layout and is not safe
authority for the current Windows 1.08 x64 Steam build. Do not patch a modern
executable from that stale offset; use save-state edits or a version-specific mod
whose current build support is explicit.
Secrets:
--------
-= Waterfall Piano Solution =-
Give an umbrella to the rain-soaked statue to hear `Memory`, then return to the
piano. The compact accepted sequence is Neutral, Up, Right, Neutral, Down, Down,
Right. The intended eight-note form may include an extra Neutral before the second
Down; the game also accepts the shorter seven-note form. The opened room contains the
Dog Residue source used for the repeatable Tem Shop farm.
-= Wishing Room Wall - Press Confirm at the North Wall =-
In the Waterfall Wishing Room, walk to the northern wall and press the confirm key to
reveal the hidden passage. The nearby telescope supplies the clue. This is a
mandatory route operation on normal routes; on Genocide the wall is already open.
-= Glyde - Hidden Snowdin Encounter =-
Before fighting Papyrus, enter the cave by the Mysterious Door in Snowdin and keep
moving for roughly two minutes to trigger Glyde. Do not kill fleeable Snowdin
monsters first if you are specifically trying to preserve the encounter conditions.
Glyde is optional and not required for Genocide.
-= So Sorry - One-Hour Clock Window =-
On PC, set the system date to October 10 and enter the Art Club room in Hotland
between 08:00-08:59 or 20:00-20:59 to trigger So Sorry. The encounter becomes
unavailable after the Undyne-letter state disables normal encounters and is
inaccessible on Genocide. Restore the correct system clock afterward.
-= Sans Room and Workshop Keys =-
Reach Sans's Last Corridor judgment at 0 EXP, then reload without saving and repeat
the judgment enough times for Sans to acknowledge the repetition and give you his
room key. Inside the room, find the Silver Key to open the hidden workshop behind the
house.
-= Two Hidden Name/Title Inputs =-
Entering `Gaster` as the fallen-human name immediately returns to the intro instead
of creating a normal file. On the PC title screen, typing `BALL` plays a hidden
melody. Neither input unlocks progression, but both are intentional PC secrets rather
than crashes or keyboard faults.
-= The Mystery Key Opens Mettaton's Old House =-
Bratty and Catty sell the Mystery Key for 600G. Use it on the locked pink house next
to Napstablook's home in Blook Acres. The room contains Mettaton's old diaries and
background story; the key is not for Snowdin's Mysterious Door.
-= Useful FUN Event Ranges =-
* 2-39 -> Wrong Number Song candidate.
* 40-45 -> Sans refrigerator call candidate.
* 46-50 -> Alphys pizza call candidate.
* 56-57 -> Nightmare Word Search.
* 61 / 62 / 63 -> the three Gaster Follower events.
* 65 -> Sound Test candidate.
* 66 -> false hallway candidate; the gray door can contain the mystery-man event.
* 80-89 -> Clam Girl.
* 90-100 -> Goner Kid.
The game randomizes fun from 1 to 100 on a RESET. Some events also have their own
chance or route/room condition, so a matching value creates eligibility rather than a
guaranteed appearance.
-= Punch Card Is a Specialist Cutscene-Movement Exploit =-
The Punch Card can be used on a one-frame timing window to regain movement during
certain cutscenes, enabling wrong-warps and sequence breaks. It remains relevant to
modern PC speedrunning, but the timing and downstream states are specialist
territory. Keep a backup before experimenting and do not use it as the normal
solution to story progression.
Solutions:
----------
-= Toriel Will Not Let Me Leave =-
1. Choose MERCY -> Spare repeatedly instead of attacking.
2. Continue even when she insists that fighting is the only way forward; she becomes
spareable after repeated refusals, with the full sequence taking 24 Spare
attempts.
3. If your HP becomes very low, her fireballs begin avoiding the SOUL, so do not
panic and switch to FIGHT just to survive.
-= Papyrus Keeps Capturing Me =-
1. Keep using nonlethal ACT/MERCY play until his name becomes spareable, then Spare
him.
2. Papyrus cannot normally kill you; a fatal hit leaves you at 1 HP and ends the
attempt in capture instead.
3. If you only want past the fight, lose to him three times and he offers to let you
skip the battle. For True Pacifist, still visit his house afterward and complete
the hangout/date.
-= Undyne Will Not Become Spareable =-
1. During green-SOUL phases, block spears by pressing the direction they arrive from.
2. When the SOUL turns red, choose Flee immediately and run toward Hotland.
3. Repeat the fight-and-flee cycle until you cross into Hotland and Undyne collapses.
4. Take water from the cooler and pour it on her before leaving. This preserves the
later friendship gate required for True Pacifist.
-= Muffet Is Draining My Healing Stock =-
1. If you still have a Spider Donut or Spider Cider bought in the Ruins, use it
during the battle.
2. Muffet recognizes the purchase and ends the fight after the following dialogue
instead of forcing the full pattern set.
3. Without the item, survive through turn 17; she becomes spareable after the
telegram resolves the misunderstanding.
-= Mad Dummy Will Not Take Normal Damage =-
1. Do not try to solve the fight with FIGHT or ACT; Mad Dummy is incorporeal.
2. During the normal dummy-bullet attacks, move so the projectiles curve into Mad
Dummy instead of your SOUL.
3. Keep redirecting those attacks until the dummy minions are replaced by robots.
4. Survive the robot/knife turns. Napstablook eventually interrupts and ends the
battle; there is no ordinary Spare command you must unlock.
-= Hotland Floor 1 Reactivated Door =-
1. Solve the right shooting board: press Up or Down, then Left or Right, then fire
twice.
2. After Alphys disables the laser, solve the left board: Up, Left, Down, Left, then
fire twice.
3. Completing both boards opens the northern door.
-= MTT News Bomb Defusal =-
1. After choosing the news item, Mettaton reveals six bombs and starts a two-minute
timer.
2. Touch a bomb to enter its battle, wait until it passes through the green DEFUSE
ZONE, then use ACT -> Defuse or hit it with FIGHT while it is inside the zone.
3. Repeat for all six bombs. The final minute slows, giving roughly twenty extra
seconds beyond the displayed two-minute pace.
4. Missing the deadline does not kill the run or block the route: Alphys disables
the large bomb and the story continues.
-= Royal Guards RG 01 and RG 02 Will Not Turn Spareable =-
1. ACT -> Clean Armor on RG 02.
2. During the next attack, touch five green projectiles instead of avoiding them.
3. After RG 02 removes his armor, ACT -> Whisper on RG 01 and tell him to be honest
about his feelings.
4. Their conversation resolves the encounter; choose MERCY when both names turn
spareable.
-= Hotland Floor 3 Reactivated Door =-
1. Solve the north shooting board with Left, Right.
2. Solve the south board with Left, Up, Left, Left, Right.
3. Both boards must be complete before the far-right door opens.
-= CORE Sage Path Shooting Puzzle =-
1. Take the western Sage path in the CORE branch if you prefer a puzzle over the
Warrior path battles.
2. For the shooting board, use: Up, Up, Left, Down, Left, Down, Left.
3. Flip the resulting switch and continue toward the CORE exit and Mettaton.
4. If you want neither route, take the eastern path and wait by its force field for
more than 60 seconds. The barrier eventually dissipates on its own.
-= Mettaton EX Ratings Are Stuck =-
1. Treat Ratings as the win condition. Pose becomes much stronger at low HP; Boast
keeps adding Ratings until you are hit.
2. Equip an armor piece you have not already worn in this battle for a large one-time
fashion bonus. Using the Stick once also gives a strong Ratings boost.
3. In yellow-SOUL shooter phases, hit the marked targets and Mettaton's exposed heart
when available. Shooting the heart shortens the attack.
4. MTT-brand food is useful when you need healing and Ratings together: Glamburger,
Face Steak, Starfait and Legendary Hero all contribute.
5. Reach 10,000 ratings after his arms and legs are gone, or 12,000 while they
remain, to end the battle peacefully.
-= Asgore Destroyed the MERCY Button =-
1. If you have 0 EXP, use Talk three times to lower Asgore's attack and defense.
2. Use the Butterscotch Pie if needed; it fully heals you and lowers his stats
further.
3. You must FIGHT Asgore until his HP reaches zero because normal MERCY is
unavailable during the battle.
4. At zero HP, choose the final FIGHT or MERCY decision. The first Neutral sequence
proceeds to Flowey either way.
-= Omega Flowey Keeps Resetting the Fight =-
1. Survive until each human SOUL interruption begins. During a SOUL phase, use the
ACT option when it appears to call for help.
2. The hostile objects then turn green and heal you. Complete all six SOUL phases;
completed phases remain cleared across deaths/reloads in this battle.
3. After all six SOULs rebel, Flowey's defense collapses. Keep attacking through the
Finale sequence.
4. At the final trap, use ACT again when the SOULs respond, then make the closing
choice after Flowey is defeated.
-= True Lab Amalgamates Will Not Turn Spareable =-
1. Memoryhead -> ACT `CELL`, then choose Refuse. This makes the group spareable.
2. Endogeny -> Beckon, Pet, Play, Pet, Pet. A Hush Puppy or Stick can pacify it
immediately for story progress.
3. Lemon Bread -> use Hum, Flex and Unhug in any order.
4. Reaper Bird -> use Pick On, Pray and Mystify in any order.
5. Snowdrake's Mother -> choose Joke three times. The encounter ends and the Blue Key
becomes available.
-= True Lab Power Door Is Still Locked =-
1. Red Key -> turn on the three sinks, spare Memoryheads, then insert the key at the
red slot.
2. Yellow Key -> search the middle-right bed in the bedroom; insert it in the VHS
room.
3. Green Key -> open the bathtub curtain on the route toward the DT machine; insert
it in the room beyond the fridges.
4. If the fake SAVE Point blocks the DT-machine route, spare Lemon Bread first; it
is a required Amalgamate gate, not a broken SAVE point.
5. Blue Key -> turn on the fan, inspect the fifth fridge and spare Snowdrake's
Mother; insert it after the bedroom mirror corridor.
6. Return to the central door, enter the power room and start the generator.
-= Asriel Cannot Be Damaged Normally =-
1. Use ACT/SAVE instead of treating the battle as a normal damage race.
2. During the Lost Soul sequence, SAVE the six friends by selecting their names and
using the dialogue/actions that remind them who they are. Restoring each pair also
heals you.
3. After all six are restored, choose SAVE again and select `Someone else` to advance
the finale.
-= Undyne the Undying Is Overwhelming Me =-
1. Equip Cloudy Glasses and Torn Notebook if you need more invulnerability time
rather than raw attack.
2. Carry strong healing, including Snowman Piece or other large heals you are willing
to spend; Temmie Armor is unavailable on Genocide.
3. In green mode, prioritize correct directional blocks over attacking quickly. In
red mode, focus on clean movement before greedily selecting FIGHT.
4. The fight must be won by damage; there is no Genocide spare route. Practice
surviving each pattern family instead of restarting after every small hit.
-= Sans Dodges Every Attack =-
1. Keep choosing FIGHT. Sans dodges the attacks, but each attack advances the
scripted battle; ACT and MERCY do not replace that progression.
2. Use Burnt Pan if you value stronger healing and bring the best Serious-Mode food
you saved. Cloudy Glasses/Torn Notebook can also help by extending invulnerability
and slowing KR damage pressure.
3. After 24 dodged attacks, Sans offers MERCY. Accepting it triggers the false-mercy
kill; use the safe dialogue window to heal instead, then continue FIGHT.
4. Survive the final attack and wait through Sans's attempt to stall your turn until
the game allows the closing input.
-= True Pacifist Quest Will Not Start after Omega Flowey =-
1. Confirm you have 0 EXP / LV 1. Any saved monster kill blocks the route.
2. Confirm Papyrus was befriended at his Snowdin house.
3. Confirm you fled Undyne, poured water on her in Hotland and completed her house
event with Papyrus.
4. Reload the Neutral-end SAVE and backtrack from CORE toward MTT Resort until Undyne
calls. Free one carried inventory slot if needed, then collect her Letter at
Papyrus's house.
5. Deliver the letter to Alphys, finish the date and return to the Lab after Papyrus
calls. The former bathroom now leads to the True Lab.
Technical Issues:
-----------------
-= Could Not Initialize D9 or D3D Surfaces =-
This is the long-standing Windows launch failure covered by the official
troubleshooting page. Close other graphics-heavy programs, reduce display resolution
if needed, update the graphics driver and install/update the DirectX runtime before
assuming the save is corrupt. If the problem persists, collect the exact error,
Windows version and store/provider when contacting support.
-= Old Windows 10 Slowdown Reports Are Patched in 1.08 =-
Version 1.08 specifically fixed slowdown on some Windows 10 PCs. If the current build
still runs slowly, do not apply an old 2017 lag-fix executable first; verify that you
are actually running the current public build, then troubleshoot modern
display/driver conditions.
-= Steam and GOG Have Different Recovery Boundaries =-
Steam supplies cloud-backed user state for Undertale even though it is not configured
as ordinary Auto-Cloud, which matters most for Genocide consequence files. GOG is
DRM-free and can run without Galaxy; Galaxy cloud saving is optional but can still
restore files if enabled. Keep provider-specific cloud behavior in mind before
deleting route state.
-= PC Does Not Include Console-Only Rooms and Extras =-
Do not search the Windows build for console-specific content such as the PlayStation
Dog Shrine, Switch Mad Mew Mew room or Xbox Dog Casino. The official PC/Mac/Linux
branch also does not use the console trophy/border additions. Those are product-line
differences, not missing PC unlocks.
-= No Audio and an Unresponsive Window =-
1. Close UNDERTALE.
2. Open `%APPDATA%\alsoft.ini` if that file exists and make a backup.
3. Remove the lines `drivers="wasapi,"` and `periods=3`, save the file and relaunch.
4. Use this only for the matching no-audio/frozen-window symptom; `alsoft.ini` can
affect other OpenAL software too.
-= Controller Is Missing or the Wrong Device Responds =-
1. Close the game and disconnect unused controllers or virtual gamepad devices.
2. Connect the intended controller before launching UNDERTALE.
3. Open Settings -> JOYSTICK CONFIG and run the control test. Adjust direction mode
or analog sensitivity there before using external remapping.
4. If two input layers are active, test native mapping and Steam Input separately so
one physical button is not being translated twice.
-= Annoying Dog Error Screen after a Save Edit =-
Dogcheck means the loaded room/state combination is invalid or the SAVE is badly
corrupted. Stop launching the damaged pair repeatedly: when UNDERTALE reloads, it
normally copies `file0` into `file9`, which can overwrite a still-useful autosave.
1. Close the game and copy the entire UNDERTALE folder before another launch.
2. Restore the untouched full-folder backup first if you have one.
3. If no backup exists and `file9` still predates the bad edit, preserve copies of
both files. Rename the bad `file0` aside, copy `file9` to `file0`, and keep a
second copy named `file9`.
4. Relaunch once. If the save works, create a fresh external backup immediately.
If both files already contain the bad state, there is no guaranteed automatic
rollback; reconstruct deliberately instead of repeating blind room edits.
Reference:
----------
-= Route Quick Lookup =-
* Neutral -> reach Asgore without satisfying True Pacifist or Genocide; Omega Flowey
is the first-run final boss.
* True Pacifist -> complete one Neutral ending, keep 0 EXP, befriend
Papyrus/Undyne/Alphys and clear True Lab.
* Genocide -> exhaust every area quota plus required named encounters, then defeat
Undyne the Undying and Sans.
* Hard Mode -> name the fallen human `Frisk`; ends after the Ruins.
-= Genocide Kill Counters =-
* Ruins -> 20.
* Snowdin -> 16 plus required Snowdrake/dog encounters.
* Waterfall -> 18 plus Shyren and Glad Dummy.
* Hotland + CORE -> 40 combined plus Royal Guards and Muffet.
-= Pacifist Friendship Chain =-
* Papyrus -> spare -> Snowdin house date/hangout.
* Undyne -> flee -> pour water -> Waterfall house event at 0 EXP.
* Alphys -> finish Neutral -> Undyne Letter -> Alphys date -> True Lab.
-= Boss Shortcut Lookup =-
* Toriel -> keep choosing Spare; full refusal sequence is 24 Spares.
* Papyrus -> spare normally or lose three times for his battle-skip offer.
* Undyne -> block green spears; flee whenever the SOUL turns red.
* Muffet -> use Ruins Spider Donut/Cider, or survive through turn 17.
* Mettaton EX -> 10,000 ratings after limbs are gone; 12,000 with limbs intact.
* Asgore -> Talk three times at 0 EXP; Pie weakens him; fight to zero HP.
* Omega Flowey -> ACT during all six SOUL phases to turn attacks into healing.
* Asriel -> SAVE six Lost Souls, then SAVE `Someone else`.
-= High-Value Item Lookup =-
* Butterscotch Pie -> full heal; weakens Asgore.
* Burnt Pan -> healing items restore 4 extra HP while equipped.
* Instant Noodles -> 90 HP in Serious Mode.
* Legendary Hero -> 40 HP, temporary attack boost, +300 Mettaton ratings.
* Cloudy Glasses / Torn Notebook -> longer post-hit invulnerability.
* Temmie Armor -> powerful death-discount armor; unavailable on Genocide.
-= Secret Lookup =-
* Waterfall piano -> Neutral, Up, Right, Neutral, Down, Down, Right.
* So Sorry -> October 10, 08:00-08:59 or 20:00-20:59, Art Club room.
* Glyde -> move in the Mysterious Door cave for about two minutes before Papyrus.
* Mysterious Door -> dodge every Kickstarter name in True Pacifist credits.
* Sans room -> repeat the 0-EXP Last Corridor judgment by reloading without saving.
* FUN 66 -> fake hallway candidate; gray door has a separate mystery-man chance.
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CheatBook DataBase 2026 is a freeware cheat code tracker that makes hints, tips, tricks
and cheats (for PC Cheats, Walkthroughs, PSP, Sega, iPhone, Wii U, Playstation, Playstation
2, XBox, Playstation 3, Nintendo 64, DVD, Gameboy Advance, Gameboy Color,
N-Gage, Nintendo DS, gamecube, XBox 360, Dreamcast, Super Nintendo) easily
accessible from one central location. (Release date January 10, 2026)
- All Cheats and Codes inside from the first CHEATBOOK January 1998 until today.
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