On several occassions the triangle dude got stuck behind or between some shapes and I had to restart the game. :(
I had some difficulty figuring out how to control it at first, but I figured out to assume the mouse was the center of a circle and the triangle would jump in an arc around it. (And then I figured out keyboard controls too oops, which probably would have solved my first issue.)
I like the aesthetic of black and white on red, and I think it's pretty cool how you got it all done up in an html file. I don't understand the components of the story. Billy is on one screen and can never be found, and the audio is slightly creepy and says it's an infinite paradox that you'll never escape, which seems to be true for the game, and also something about how Billy was never there in the first place (I thought I heard Billy as god the first time I played through, which I'm not sure about). I got to the point where the audio turned into a constant loud distorted mess and went through a bunch of screens, but I couldn't find anything so I gave up.
Knowing that pressing 's' would restart the level was very useful.