This article contains a collection of changes found in newer versions of Undertale.

UNDERTALE v1.001v1

This update was issued on March 8, 2016, and comes with an update to the steam_api.dll to ensure Undertale works with the latest steam client update.[1]


For the changes shown as images, see here.

Toby Fox first announced UNDERTALE v1.001 on January 12, 2016.[2] Beta testing for UNDERTALE v1.001 began on January 19, 2016, and was only available for those with the Steam version of UNDERTALE.[3] This version of UNDERTALE was later deemed official on January 20, 2016[4], and was later made available for those who bought the DRM-free version of UNDERTALE on January 21, 2016.[5]

  • Added a splash screen, which appears to be a stretched 320 x 80px image of the UNDERTALE logo.
  • The version number of UNDERTALE was changed.
  • Changed the Joystick Config menu so that "JOYSTICK CONFIG" is now bolder, the seasonal message is no longer italicized, and "Analog Sensitivity Sensitivity" now have spaces in between them.
  • Added a third dash to the right of the word "Instruction" in the game's instruction menu.
  • Removed the ability to wallhump and walk left at the same time, so the protagonist is unable to face up or down in dramatic scenes when they're supposed to be facing left. "Wallhumping" and walking right is still possible, however.
  • Added a proper kill animation for Ice Cap when in ice form.
  • Changed the color of light blue attacks to 00A2E8 (from 42E2FF), to be more visible to color blind people.[6]
  • Added dialogue for calling Papyrus in the Electric Maze room for when the protagonist walks over the Electric Maze in a failed Genocide Route.
  • Added extra dialogue for Papyrus in Papyrus's Room when inspecting the box of attacks that he did not use, including his special attack which would have been able to blast the protagonist's SOUL. Papyrus will then talk about the Annoying Dog again once he realizes that the dog has stolen his special attack again.
  • Fixed a glitch where if Papyrus is killed and the protagonist walks to the left in the scene where Undyne spots them, Papyrus would appear on the left side of the screen.
  • Added the solution to the Piano Puzzle to show up on the screen when listening to the statue's music box.
  • Changed Clam Girl's dialog to make it clear that the protagonist cannot meet "Suzy," adds the word "today" to the end of "But there's a limit to the things you can do." and adds an extra line to Clam Girl's dialogue suggesting that Suzy may be the reason the protagonist is there.
    • Added a poorly drawn picture of three smiling people with "don't forget" written on it which will appear inside the first drawer in Sans's Workshop if the protagonist has spoken to Clam Girl.
  • Added an audio file called Grandpa Temi which plays when Temmie is denied the Temmie Flakes.
  • Changed the hitbox of the dog food back in the Lab to prevent the "Lab Skip" from being done.[7] (It didn't work.)[8]
    • Changed calling Papyrus twice in the Lab from "DID YOU TELL HIM?" to "WAIT, THAT BAG OF DOG FOOD LOOKS FAMILIAR... I REMEMBER SEEING... IN SANS'S ROOM? YEAH! I ASKED HIM WHY HE HAD IT! HE TOLD ME HE WAS TRYING TO EAT HEALTHIER." as a possible explanation for this change.
  • Changed the position of the bathroom sign and the switch around near the entrance of the True Lab.
  • Added extra dialogue for Burgerpants which are "Clarify Story" which is Burgerpants explaining that he had to throw away all of his clothes to make room for the outfits that Mettaton gave him and "Outing" which is Burgerpants talking about how the Nice Cream Guy talks to him about the jokes on his ice cream wrappers and how he gets free Nice Cream from him.
  • Fixed a glitch where the protagonist would be able to grind enemies in the CORE and reach LV 14 on a True Pacifist Route.
  • Changed the beginning of Sans's fight so that Sans can say "ready?" and "here we go." when the protagonist dies enough times, rather after the protagonist beats Sans once.
  • Fixed a bug where pressing the spacebar key would cause the Alphys and Undyne kissing animation to begin in the faux Asgore Dreemurr battle in the True Pacifist Route.
  • Removed the empty space and stray pixel found near Mettaton EX in the full version of the Start Menu.
  • Changed the positions of the Amalgamates in the True Pacifist Ending Credits.
  • Added four lines of dialogue when attempting to fight the Annoying Dog in the room beyond the Mysterious Door about the holes in the fabric the dog is sleeping on and the idea of a crocheting dog.
  • Changed abc_123_a.ogg, an audio file that originally had text-to-speech told the listener not to post the game's secrets online, into laughter.
  • Changed "abc_1111_0.png", an image that originally told the reader "don't upload these huge spritesheets online," with an image about "bepis" which is just a word that Toby Fox thinks is funny.[9]
  • Removed the "Fun" value, which essentially means that the "Fun" value no longer needs to be modified to find W. D. Gaster and other related "Fun" events.
  • Fixed various typos.
    • Fixed a typo in Muffet's dialogue when she says "And we'll also be able to afford...!"
    • Removed the second "If I" in Undyne's dialogue when the protagonist repeatedly fails to use the shield correctly.
    • Fixed "PIRAHNAS" to "PIRANHAS" when Papyrus explains the Multicolor Tile Puzzle.
    • Fixed the asterisk and quotation mark in the "BONELY" line of Toriel's diary entry.
    • Fixed the dialogue for Snowdrake's Father from "these" to "this" when talking about his son's jokes.
  • Changed ATK and DEF stat that shows up when a monster is checked, presumably because all monsters had an ATK and DEF stat of 10 or less, which meant they were as powerful as the enemies found in the Ruins. This does not change their actual in-game stats, however.
All UNDERTALE v1.001 Stat Changes

  • Stronger Moldsmal: "ATK 6 DEF 0" to "ATK 12 DEF 0"
  • Ice Cap: "ATK 7 DEF 2" to "ATK 11 DEF 4"
  • Jerry: "ATK 0 DEF 20" to "ATK 0 DEF 30"
  • Lesser Dog: "ATK 7 DEF 0" to "ATK 12 DEF 2"
  • Greater Dog: "6 ATK 4 DEF" to "ATK 15 DEF 8"
  • Papyrus (Neutral): "8 ATK 2 DEF" to "ATK 20 DEF 20"
  • Papyrus (Genocide): "5 ATK 5 DEF" to "ATK 3 DEF 3"
  • Gyftrot: "7 ATK 3 DEF" to "ATK 16 DEF 8"
  • Dogamy and Dogaressa: "6 ATK 4 DEF" to "ATK 14 DEF 5" (for both)
  • Doggo: "6 ATK 1 DEF" to "ATK 13 DEF 7"
  • Snowdrake: "6 ATK 2 DEF" to "ATK 12 DEF 7"
  • Chilldrake: "6 ATK 2 DEF" to "ATK 12 DEF 7"
  • Woshua: "7 ATK 1 DEF" to "ATK 18 DEF 5"
  • Shyren: "7 ATK 2 DEF" and "7 ATK -150 DEF" to "ATK 19 DEF 0"
  • Undyne (Neutral): "7 ATK 0 DEF" to "ATK 50 DEF 20"
  • Undyne (Rematch): "10 ATK 10 DEF" to "ATK 41 DEF 21"
  • Mad Dummy: "7 ATK -40 DEF" to "ATK 30 DEF YES"
  • Aaron: "7 ATK 2 DEF" to "ATK 24 DEF 12"
  • Temmie: "7 ATK -20 DEF" to "RATED TEM OUTTA TEM"
  • Moldbygg: "ATK 6 DEF 0" to "ATK 18 DEF 18"
  • Mettaton (Box): "10 ATK 999 DEF" to "ATK 30 DEF 255"
    • Added two extra check dialogues that puts emphasis on how Mettaton's metal body is invulnerable.
  • Royal Guards: "8 ATK 4 DEF" to "ATK 30 DEF 20" (for both)
    • Added check dialogue for RG03, even though they can't be encountered ingame.
  • Tsunderplane: "8 ATK 6 DEF" to "ATK 25 DEF 26"
  • Vulkin: "8 ATK -10 DEF" to "ATK 25 DEF 0"
  • Pyrope: "8 ATK 1 DEF" to "ATK 29 DEF 14"
  • Muffet: "8 ATK 0 DEF" to "ATK 38.8 DEF 18.8"
  • Madjick: "8 ATK -1 DEF" to "ATK 29 DEF 24"
  • Knight Knight: "8 ATK 2 DEF" to "ATK 36 DEF 36"
  • Final Froggit: "8 ATK 0 DEF" to "ATK 30 DEF 24"
  • Astigmatism: "8 ATK -2 DEF" to "ATK 32 DEF 26"
  • Whimsalot: "8 ATK -3 DEF" to "ATK 34 DEF 12"
  • All Bombs (except the Annoying Dog): "1 ATK 0 DEF" to no stats. (Note: The Annoying Dog was the only bomb that did not have stats before this update.)
  • Mettaton EX: "8 ATK 1 DEF" to "ATK 47 DEF 47"
  • Reaper Bird: "9 ATK 9999 DEF" to "ATK ?? DEF ??"
  • Snowdrake's Mother: "0 ATK 0 DEF" to "ATK -12 DEF -5"
  • Migospel: "7 ATK 3 DEF" to "ATK 28 DEF 17"
  • Parsnik: "7 ATK -2 DEF" to "ATK 30 DEF 28"
  • Moldessa: "7 ATK -4 DEF" to "ATK 27 DEF 23"


UNDERTALE v1.00 was the first complete version of UNDERTALE that was released on September 15, 2015.


  1. "If anyone got an UNDERTALE "update" on steam it was just a change to a DLL to ensure UNDERTALE works with the latest steam client update" - Toby Fox. March 9, 2016. Twitter.
  2. "Will release the bugfix patch soon after some more testing of it. Nothing to really be excited about. I think it will work on El Capitan now" - Toby Fox. January 12, 2016. Twitter.
  3. "Got a lot of e-mails saying UNDERTALE won't launch on Steam. Steam's latest (beta?) update may be incompatible on some Windows computers." - @UnderTale. January 19, 2016. Twitter.
  4. "UNDERTALE was updated on Steam to fix bugs and increase compatibility." - @UnderTale. January 20, 2016. Twitter.
  5. "DRM-free version was updated. If you want to download the new version, find the download link in your e-mail or use" - @UnderTale. January 21, 2016. Twitter.
  6. "In patch, color of blue attacks will be changed to be more visible to colorblind some people. (This should be blue?)" - Toby Fox. January 19, 2016. Twitter.
  7. "so far bugfixes include shrinking the hitbox of a bag of dog food" - Toby Fox. January 10, 2016. Twitter.
  8. "well it's at least harder to do now (?) i couldn't figure out how to do it so its probably ok if its just a speedrun thing" - Toby Fox. January 20, 2016. Twitter.
  9. "i swear the president is gonna play my game or smth, he gets to some dramatic scene and then the character will just say "bepis"" - Toby Fox. January 26, 2015. Twitter.