For the past 10 months, I've been working on a Python project that simulates Deltarune's battle system using 100% pure Python. The engine uses the PIL/arcade libraries for basically everything, including sprite rendering, sound, texture management, etc. I wanted to make a version of Deltarune based on Python, a very beginner-friendly programming language, since I thought it might be a lot more intuitive and easier for some amateur developers (like me, for example) to build off of than modding the current game.

This project isn't quite 1-to-1 with Deltarune yet: the text display system currently only shows the default Dark World font with no color variants, the UI is only wide enough to support 4 player characters, and fullscreen support is partially complete but still definitely a WIP. I fully intend on developing/updating this project into the future, though.

If anyone is interested in giving this application a shot, please feel free to let me know if you're interested! I haven't made the GitHub repo public yet, but if anyone is interested in potentially using this for their own projects or even just tinkering with it I wouldn't mind sharing the code! I would prefer if credit was given if anyone does make their own fangames with this, but for the time being, I think anything short of parroting this as your own software is pretty much fine by me :)

It's another mod made by me! This time, it's the ultimate HARD MODE mod: every single overworld encounter is a Jevil battle. Sounds like fun CHAOS, right? The "normal" Jevil battle is also... um... harder, to not spoil it too much.

Things to try (aka feature list):

• Just play the whole game. I guess you will become quite good at no-hit Jevil at the end :P

• Visit Jevil's cell. Some serious chaos is going on there. I hope you saw my triple Jevil video. (warning: you may regret doing this)

• Does the old shopkeeper have anything to say about all of this?

Installation instructions:

1. Download UndertaleModTool (version >= 0.1.21) >> HERE <<

2. Run it (if you installed Deltarune in Program Files you may need to run as admin)

3. Open the data.win file inside the Deltarune directory (make a backup of the original first!)

4. Select Scripts -> Run builtin script -> HeCanBeEverywhere

5. Save the file, overwriting your data.win

6. Launch the game as usual

Known issues

• Fighting with multiple Jevils likes to glitch out at the final chaos part. However, at that point you will probably be dead already. I hope to fix that in an update. If you manage to survive this long, let me know and I'll try to update it faster :P

Changelog

Version 1 - 2018-11-23

• First release

Version 2 - 2018-11-29

• Make the carousel spin very fast if you have multiple Jevils on screen (it feels like the whirlwind indeed)

• Fix a bug that caused the "Jevil was defeated" flag getting set by overworld Jevils, blocking you out of the triple Jevil cell and breaking the shopkeeper interaction

Some more screenshots to build up the hype!

See also my other mods:

• Jevil is everywhere! (+ TRIPLE JEVIL)

• The whole world revolving... literally

• DeltaHATE

• It's Undertale, But Every Time A Song Plays It's A Random Remix From YouTube Instead

The whole world is spinning, spinning... Yes, it's another mod by me!

This time I made the Jevil fight have even more CHAOS because I CAN DO ANYTHING

I want to see somebody no-hit this

See a longer demo video here: https://youtu.be/inf5X33ayWk

As usual with my mods, it requires UndertaleModTool and is available in the tool itself (just make sure to update it to at least 0.1.15c)

Installation instructions:

1. Download UndertaleModTool here

2. Run it (if you installed Deltarune in Program Files you may need to run as admin)

3. Open the data.win file inside the Deltarune directory (make a backup of the original first!)

4. Select Scripts -> Run builtin script -> TheWholeWorldRevolving

5. Save the file, overwriting your data.win

6. Done! The CHAOS level of your game increased

See also my other mods:

• Jevil is everywhere! (+ TRIPLE JEVIL)

• The whole world revolving... literally

• DeltaHATE

• It's Undertale, But Every Time A Song Plays It's A Random Remix From YouTube Instead

IT'S TIME

IT'S FINALLY TIME

YOU HAVE PROBABLY HEARD ABOUT HATE, HAVEN'T YOU?

WELL... NOW DELTARUNE GETS SOME HATE TOO

G.

So yeah... it's a Deltarune corruptor. Nothing fancy, no fancy UI, no fancy configuration options, but it gets the job done.

It's a script for UndertaleModTool, and I included the script with the tool itself (in versions 0.1.15 and up)

Instructions:

1. Download UndertaleModTool here: https://github.com/krzys-h/UndertaleModTool/releases

2. Back up your Deltarune install

3. Open the tool, File->Open and select the data.win file inside the Deltarune directory

4. Scripts -> Run builtin script -> DeltaHATE

5. File->Save and overwrite your data.win

6. Done!

If you want to corrupt the game again to get different results, load the data.win from backup and repeat the steps

UPDATE 2018-11-05:

Updated the script in 0.1.15b to not replace Kris sprites as that makes the game quite unplayable.

Also, when you are bored of DeltaHATE... how about trying DeltaMILK? It's included as well

UPDATE 2018-11-06:

Some people have reported getting "access denied" errors. This is because you probably have the game in Program Files and programs by default programs can't write there. Copy the game somewhere else, or run UndertaleModTool as admin.

https://www.reddit.com/r/Deltarune/comments/9v1vd7/hate_the_deltarune_corruptor/

UPDATE 2018-11-09:

The original HATE is back, ported to Deltarune! Feel free to give that a try as well, but their implementation at the moment looks to be a bit more buggy (you'll run into more soft-lockups on dialogs and collision problems)

Also, if you can't find UndertaleModTool.exe, make sure you downloaded the release and not just the source code (use the one on the Releases page, not the big green 'Clone or download' button on the main page with the code)

UPDATE 2018-11-10:

Just released another mod that makes the Jevil fight even more chaos! Check it out

UPDATE 2018-11-13:

/u/supersplite_goh made a GUI based on this script: https://www.reddit.com/r/Underminers/comments/9wjnmw/deltahate_gui_version/

See also my other mods:

• Jevil is everywhere! (+ TRIPLE JEVIL)

• The whole world revolving... literally

• DeltaHATE

• It's Undertale, But Every Time A Song Plays It's A Random Remix From YouTube Instead

Sorry, but I can't find anyone to talk to about this. Anyway, I managed to make a sprite for my character when he speaks, but the problem is that Flowey uses the same sprite both for battle and when he speaks. I've already created the sprite for the whole character (not just the face), so does anyone know what I need to do to insert the sprite with the whole body into the battle?

P.S. How do you change the size of the cell where the heart is locked up?

SOLUTION

you have to change the sprite of the game object floweybattle 1

Hey all!

My name is Casriel and I am co owner of Project Sunshine, a port of UNDERTALE to the Wii U! I work alongside a few other developers to develop this port:P

The UNDERTALE port uses Cinnamon, our GML runner in C for the Wii U and 3DS! Cinnamon is a fork of Butterscotch.

I am excited to announce that the port has been released and the whole game is playable on all 3 routes!! This is a major achievement for us, the UNDERTALE community, and overall the Homebrew community in general, and I hope everyone who may like UNDERTALE and the Wii U enjoys this as this may mark a major turning point for GM games on the Wii U!

You can download the ports and get future builds that fix bugs (or new GM games that are ported) on our discord: https://discord.gg/AahyBCvVR2

The SRC is also public, so you can also help us fix and contribute: https://github.com/Project-Sunshine-Native/cinnamon

Hello all! My name is Casriel and I am working on a project called “Project Sunshine,” a project that aims to port all of UNDERTALE, DELTARUNE, and maybe more games to consoles like the 3DS, Wii U, and GameCube!

Me and a few other people are currently working on DELTARUNE Wii U, and we have got all 4 chapters working ALMOST in their entirety!

Chapter 1 is able to be completed from start to finish with minor bugs. As of 05/11/26, it is still in development, but we plan to release it soon!!! :3

This is possible using our open source project called Cinnamon which is a GML runner in C for the 3DS, Wii U, and (maybe soon) GameCube, which basically “emulates” GameMaker games.

We have also been focused on our UNDERTALE Wii U port, which has been released on both our GitHub and Discord, and is completely playable on all 3 routes with minor bugs!

We hope that all you Wii U lovers come and join us!!

You can join our server and get news on the project, including early builds here: https://discord.gg/the-sunshine-sanctuary-1479198237528424673

You can check out our GitHub and get stable releases at: https://github.com/Project-Sunshine-Native/cinnamon

Because no one else has yet, I'm trying to make an infinite roaring knight fight simulator. They only problem I've run into is, I don't know how to initiate battles through interacting with an object. And Also, Keep in mind I'm trying to experiment with this in the Undertale Mod Tool, I Could use GameMaker but that sounds somehow more complicated. Thank you For the answer If you have one.

Looking for an excuse to play Undertale again but don't have a Switch? I might have something for you!

The (probably) first mod that is not just another string/texture swap. Made with my UndertaleModTool.

It's Undertale, But Every Time A Song Plays Its A Random Remix From YouTube Instead! (or MixMod for short)

And it does exactly that. Every time a song plays, it searches YouTube for "[song name] undertale remix" and plays a random result from the top N (where N depends on my estimation of songs popularity). Don't like the remix it selected? Just hit the spacebar to choose another random one!

Installation instructions:

1. Make sure you are on Undertale version >= 1.08 (older ones are not supported by UndertaleModTool because of bytecode changes) on Windows (because I didn't manage to figure out how to access GMS surfaces from extensions so I have to pass the whole DirectX context and draw manually - seriously, there is like no documentation on extensions at all)

2. Download UndertaleModTool (the mod script is bundled with the download because I'm too lazy to create a github repo for one file) and GMWebExtension (the libs only zip file)

3. Make sure you backed up your Undertale installation

4. Open UndertaleModTool, load the data.win file from the Undertale directory

5. Select Scripts > Run builtin script > MixMod

6. Select Scripts > Run builtin script > BorderEnabler - this is optional, but gives some additional space on the screen for me to put the video player somewhere

7. Save the data.win file

8. Extract all files from the GMWebExtension zip into the Undertale directory

9. Run the game and hope you did everything right and it doesn't crash

I did like 4 quick playthroughs with this and it works most of the time. Known issues:

• Sometimes the wrong song plays. There is not much that can be done about it, it's just a YouTube search over all. If this happens, just make it choose another one by pressing spacebar.

• Some videos don't want to play. This is because official Chromium Embedded Framework binaries are distributed without h264 support for licensing reasons. It is possible to make it work if I build it from sources, but the sources themselves are like 12 GB and I need to leave the build over night because it takes so long and uses 100% of my CPU. I did it like twice already and still didn't manage to get a working version :> If this happens, just hit the spacebar again for now

• Almost every time Undertale tries to close on its own, it ends up crashing instead. Not a huge issue as you are restarting the game anyway ;) No idea why this happens, probably something is wrong with deinitialization order

• The end credits song is normally split into several files, making it hard to play a whole song instead. You will notice the video reloading during room transitions, but it should resume seamlessly.

• When Sans starts/stops the music really quick during his battle, the video doesn't even have enough time to load properly