TS!Underswap Wiki

The TS!Underswap Demo 1.0 was released on December 23, 2020, and can be downloaded from its GameJolt page. It was developed by Team Switched in GameMaker: Studio 2.


The TS!Underswap Demo 1.0 contains the first location of the full game, Ruined Home.

Main Story

(TBA: Formatting and spelling/grammar fixes.)

Chara falls down to the Underground, then they find Temmie who is the first monster to encounter you and introduces themself and the mechanics of the game however after tricking you with Tem Flakes, they attempt to take Chara's soul but retreats since they saw Asgore. Asgore finds the human hurt and heals them, he acts very friendly to the human and assists Chara throughout the Ruins by helping them with puzzles and talks to them about history of monsters and humans. Throughout the journey Asgore shows Chara the Dummy and teaches Chara more of the mechanics of the game however after Chara says goodbye to the Dummy, the Dummy says that he has enough and reveals themself to be the Mad Dummy. He attempts to attack Chara with his knive but isn't able to kill Chara or depending on the actions misses, Mad Dummy says that he'll be back and that he's mortal rivals with Chara. After a couple more rooms, Asgore says that he has urgent business to attend (possibly that Mad Dummy is causing havoc in the Ruined Home) leaving Chara alone, they do puzzles and encounter monsters. After that Chara faces of against the Ruined Knights then after completing all of the puzzles in order to go to the City of Old when going across the bridge they fall down to The Sewer thanks to the Mad Dummy destroying the bridge, after recovering from the fall they solve another puzzle and avoid burning water (which actually can kill you) then Mad Dummy chases Chara (similarly to how the Chaos King from Deltarune's allies attack you overworld), then after Chara shuts a door right before Mad Dummy was going to through, finds City of Old through a sewer platform. Chara explores City of Old (optionaly) Chara finds Flara who begs them to help Bugerpant from The Greasers, they agree and confronts The Greasers, BugerPant thanks Chara for helping them, you can go to Grillby's Backyard Barbecue to learn more of BugerPant and buy some goodies. After that Chara faces of against Mettacrit for his show, after fighting, Chara finds Asgore at his house and Asgore spots them while talking to someone, Asgore invites them to his house and prepares Golden Flower Tea and pie. Chara goes to sleep, after sleeping they find tea and explores around the house, Chara talks to Asgore and tells him that they want to stay however their word mysteriously changed to them saying the complete opposite thus making Asgore leave the house to go and protect Chara from leaving the Ruined Home and City of Old. Asgore reveals that six humans have left and gotten killed by other monsters, he also feels like that he's failed over and over again then Asgore fights Chara in order to test if they can leave the Ruined Home.


The demo features multiple endings, depending on the player's actions and route taken. These include:



Version History

  • Version 1.0.0 - This was the first release of the TS!UNDERSWAP Demo. (Released December 23, 2020.)
  • Version 1.0.1 - Fixed minor bugs. (December 23, 2020.)
  • Version 1.0.2 - Fixed more minor bugs and tweaked encounter rates. (Released December 24, 2020.)
  • Version 1.0.3 - Fixed even more bugs, and made some minor tweaks. (Released December 26, 2020.)
  • Version 1.0.4 - Fixed when people couldn't type Z key in the GameJolt login screen. (Released December 26, 2020.)
  • Version 1.0.5 - Fixed GameJolt related bugs. (Released December 28, 2020.)
  • Version 1.0.6 - Fixed more bugs and updated the credits. (Released December 31, 2020.)
  • Version 1.0.7 - Fixed minor bugs, new quality adjustments and added official localizations for Spanish, Brazilian Portuguese and Dutch. (Released February 20, 2021.)
  • Version 1.0.8 - Fixed minor issues with the official localization files (Released March 6, 2021.)

Teasers and Trailers

Team Switched have uploaded various teasers to their YouTube channel, showcasing preview footage from the TS!Underswap Demo. The footage has been modified in order to exclude major spoilers.

Undertale: Underswap Demo Teaser

On September 17, 2016, a teaser video was uploaded for Undertale: Underswap. It features extremely outdated footage such as introduction sequence, Temmie and Asgore encounters, Ruined Home entrance, Mad Dummy tutorial battle, and several Froggit encounters. This iteration of the project was much closer to canon Underswap, and utilizes outdated assets and some recycled from the official UNDERTALE. Over the course of 2 years, the project would go through major revisions, being renamed TS!Underswap along the way.

Demo Teaser #1

On August 8, 2019, the first teaser video was uploaded. It showcases an iteration of the demo vastly updated from its original version, including: the introduction sequence, Temmie and Asgore encounters, and Ruined Home entrance.[1]

Demo Teaser #2

On November 29, 2019, the second teaser video was uploaded. The beginning of the video showcases a version of the second teaser video (which was a update from the first one) with updated visuals, an extended Temmie encounter, and the brand-new SAVE menu. It continued with the Mad Dummy tutorial battle, a new Monster Candy room, and the first Froggit encounter. At the end of the video, there was a short phone call from Asgore, implying a surprise Christmas content update. [2]

Demo Teaser #3

On December 25, 2019, the third teaser video was uploaded. It showcases short previews of level design, phone calls, brand new monster attacks, unique combo monster attacks, Journal functionality, and the Game Over sequence. At the end of the video, there was a short preview of the Genocide Route.[3]

Final Demo Teaser

On October 31, 2020, the final teaser video was uploaded. It features a brief segment of Chara standing by a patch of golden flowers in a garden, before transitioning to a TS!Underswap Demo splash screen. This is followed up by another screen with the text "Soon™," implying an upcoming release date. In the description of the video (and the corresponding GameJolt progress report), Team Switched stated the demo is 95% complete, with the final steps for development including playtesting and polishing. [4]

UnderEvent Reveal

On December 11, 2020, the UnderEvent YouTube channel uploaded an announcement video showcasing two of the fangames that will be included for its February 2021 presentation--Undertale: True Genocide, and TS!Underswap. The latter's portion consists of brief gameplay segments with updated visuals, and character dialogue.[5]

Release Trailer

The release trailer premiered on YouTube on December 23, 2020 @ 2:30 PM EST. It was a parody of Undertale's own release trailer.[6]



Video Gallery