Good grief! I ended up playing this game for four hours on an exam night. o_o
First things first: very addicting game; love the music and the sound when you make a square; the lines lighting up as I move the shape around was pretty neat.
A few things I think can be improved: rotation would be a nice idea imo. It would add some creativity to figuring out ways to make squares. Also, please, please change the sound effect when the game ends. It scared the juhbeezus out of me. ._. But overall, awesome game!