nice game
Good idea for a game. The execution is good, I didn't ran into any problems. There are few things you could improve on. First thing is the graphics, seem like they are "programmer graphics" which means really simple and not very pretty.
Second thing is the difficulty. I think the difficulty is ramping up pretty fast. I found the second level already pretty hard and had to give it several tries before beating it. And things didn't get any easier at level 3 :). Imo it's good game design to throw in some easy levels at the beginning to hook the player. I think you made these levels thinking of yourself and they probably aren't so hard for you as you made this game, but I'd like to see some easier levels at the beginning.