Wheee!!
What an amusing game! I got totally hooked up with it. It has simple graphics, okay, but that doesn't bother me at ALL. You know why? Because the true star of this game is the amazingly smooth control system you've come up with!
Very simple rules, enemies with increasing AI, super-smooth controls... It's a really fun game, very functional and amusing. Very good work!
There was only one thing I'll consider a glitch: in one moment I blasted an enemy that was almost on the edge of the "arena circle". This enemy left behind a Heal Item, but it appeared OUTSIDE the circle and so I couldn't pick it up. It's surely too nit-pick of me, but hey, this is the only real problem this awesome game has. ;-)