The music's good. I also agree that right now it's a bit repetitive.
For new mechanics maybe there could be something to collect along the way, something which forces the player to make a detour. Maybe there could be a wave of lava that appears which would force the player to quickly find a route to the other side of the stage. I'm not sure myself, just throwing stuff out.
I think the game as it is now may be a bit restricting in regard to adding new mechanics. Since you're the mouse pointer it would most likely be unintuitive/annoying to have level elements move your character. And right now it looks like it's randomly genrated levels? (of course there's already code to set the difficulty and maybe to make sure it's completable.) I think it's harder to add more mechanics when a game is basically completely generated randomly because you have to account for the randomness.