Hehe, cool! Very simple and straight to the point. It works very well.
And it's not that easy. With the variable projectile speeds, it took me a few tries to do better than 10 :p
It would be nice to have a visuel feedback after losing to know when we can hit the space bar to start anew. But, well, I'm nitpicking here. Great job!
PS : the music sounds great but it's tough to hear a lot of it ;)