This is NOT the full game, just a proof of concept for running it in a web browser.
(Particularly with being able to play layers 0 through 7 )
I did recently figure out how easy is actually is to decompile the versions of ULTRAKILL before the revamp update, but was halted due to the fact the game uses asset bundles as opposed to normally shipping it in the same package.
Essentially ULTRAKILL runs off of what is called the "bootstrap" that loads these bundles in and lets you play the game. If you decompile the bootstrap and recompile it back to windows, the game will work the same so long as you provide the asset bundles. These asset bundles are NOT cross platform. They are proprietary to platform they are made for. It could be possible to try and do some work to make them cross platform, but that is outside my skill range, especially for things like shaders, which are insanely difficult to try and accurately recreate in a way that can be compiled to other platforms.
So it could be possible to try limbo and lust with an older update without the bootstrap, but that really wouldn't be that interesting as in comparison to the newer (non-revamp) updates.
Ok I forgive you, but please I beg you and anyone else on this page not to ask me about the full version, we don't speak about level 1-2 around these parts. Besides, I'm not going to be the one responsible for doing the full version. The real madman who will be willing to do that is genizy, aka the creator of https://gn-math.dev/. I know this for a fact because I am in contact with him, and he told me that himself.
No, I have made my point crystal clear, and you are firmly ignoring me with a single article. I will NEVER port a paid game, even if everyone wants me too, I WON'T. I already paid for the game, SO SHOULD YOU. I don't care if you want me to port the full game, pirate it yourself if you're so damn insistent about piracy being "Okay".