Could you make it any more difficult?
I try to avoid reviewing games like this because my reviews usually get deleted by spammers. Anyway, the game is way too difficult past level ten. The screen just becomes a cluster of enemies and you can't move without getting killed. Also, pressing a button to go to the upgrade screen is preposterous. You have to let your guard down and it gets you killed in later levels no matter how powered up you are. Some of the power-ups like the magnet and the rapid fire just don't have any noticable differences. I think some of the power-ups are broken. Also, The arena is way too big. Loads of enemies just come right in and hit you because you couldn't see a certain area to hit them. This is especially true when the mine laying enemies come into play. I really don't think this deserved the front page, but a lot of the stuff doesn't really deserve to be there. Oh well. The story is kind of pointless. Unless there is something at the end, which I never made it that far. Try to fix some of the issues I described and this would be a perfect way to kill an afternoon.
There are a few saving points that save this from getting a 1. The controls are very easy to use, and that is always nice. I had no problems with the controls. Also, I did like the enemies. Everything seemed to blend well for the most part, but the sheer numbers in later levels literally fills the screen making movement without being hit impossible. And I mean FILLING the screen. I got to the point where all the big enemies left absolutely NO space. However, the upgrade system (while not perfect) does help, however, as mentioned, it should come up automatically when you level up. You literally have to stop moving in order to hit the pause button, and it DOES get you killed in later levels.