Yay! I completed it! Nice job, cool mechanic that really went well with the theme. I think I have a bit of an idea about how you actually did it but I'm not necessarily sure - some kind of cool material i'm sure!
Just one note is that it wasn't obvious you could run out of paint and I was a bit spammy at the start - I might put in a widget letting people know. Also I wasn't a fan of the music, i'm sure you either made it in metasounds or were going for a vibe but it wasn't for me.