Very fun and interesting concept! Your interpretation of the theme is totally out of the box thinking and I really like it. The music is super awesome, I currently have the game running in another tab just so I can listen to the menu music.
The option to disable the filter is very appreciated. It looks nice, but makes it hard to tell when I'm rainbow and can attack.
The way you did the two button diversifier was really interesting. You managed to get a good character movement with just one button, which is really unique. You should put this on mobile! It would work great with a touchscreen.
The only thing that's a bit unclear is the amount of time I'm able to attack, and when. It would be nice if there was a progress bar - like telling me how much time is left until I can't attack - just so I can get used to the timing of it.
This was a great experience overall, and I really enjoyed it.