Not bad, but needs more effort
This isn't a bad job. I enjoy it. I'll tell you a couple of good things first.
The good things:
Fun to play. Yes, it really is. I like games that are simple and fun.
Physics based. I like games with physics. The only thing that it doesn't have is the fact that when two shapes bump they do not go apart.
Now for the bad things I noticed:
Lots of lag. Laggy games are no fun when you keep losing.
Glitches for the upgrades. I couldn't upgrade very far for the rocket launcher.
Also, the gun shoots way to slow.
Good job, keep in mind the lag next time.