Really nice game, cool visuals, gameplay works well. Pausing the game when going out of bounds is good, but locking the mouse cursor would be better I feel.
Due to the music I only realized that there were no sound effects. So I didn't miss them, but I do think it would be a better experience with sound effects.
I do think it was a bit too easy, I just breezed through all the levels. Got hit 5 - 10 times in total.