Simple and good
Argh, this one is tricky! I like it. Very simple, yet entertaining. There is even a "highscore list". I didn't make it, I'm not a genius. I will try, though.
I think it would be an awesome game if it had more levels (easier ones too!) and some better interface. WASD is really a bad choice. Why not simply drag & drop? That way, you could even play it on the Wii!
Some simple, quiet sounds would also help.