Nice job!
I think that the visuals are good looking and I believe that the music really fits the game. I also really love the boss and the fact that it shot fireballs :D.
As another comment said I think the dimensions are a bit unbalanced but other then that I think its a cool concept. Also, at least the first time I played, I was a bit confused about which button changed to which dimension, so adding UI showing this when playing would be helpful.