I had fun playing the game. It took me a few tries to figure out level 2 - which is what made it fun.
I'd prefer to play with arrow keys and not WASD on keyboard.
I'd also recommend changing the block when I land on it, not when I move off it.
I do think the scrolling with the background could induce a vertigo effect if played too long on a PC screen. Perhaps on mobile it will be better.