got to level 4 before i got 'rage bored'. i'm not sure if i got lucky or did the right thing on each section, which is strange, since you usually go 'aha, i have to do X'. i like everything you got so far, but as others have said, losing the second eyeball just forces you to self smash again, so maybe just restart automatically when the eyeball settles on the ground. i did like the whole eyeballs thing, but maybe you could incorporate damage as being a function of speed and angle of impact, so basically mashing your head when the dot product is 1 (or is it -1 ?) should kill you instantly.
i feel like you could have a lot more easy levels before the ones you got now, just so the player can get used to the movement, and maybe even some arrows on the background telling how you are supposed to go over it acting as a tutorial of sorts on the first challenges.
played the web build with Chromium and iGPU and performance was fine.