Wow, I really liked this. Everything's so smooth. The movement, the shooting fireball mechanics, and the various particle effects. I also really dig the art style. The glowing blue and red are amazing to look at. The level puzzles are challenging but not too difficult and slowly eases you into more complex levels.
I assume because of the timeframe we had, you weren't able to implement audio? That's understandable. You have a really good game here, though. It's super fun.