Good stuff. The glitchy gui was already brought up in other comments. I had fun while playing, and I wish there were more levels.
Visuals and audio were great. It's always easier to play a puzzle game that is pleasant to the senses, and you did a good job with that.
Oh, one thing you could add that I think would add to the layout is a background for where the modifiers spawn. It would feel like that's "their spot", if you know what I mean, and would look less like they're just plopped onto the screen.
Awesome job!
-Zachary