Good intentions with serious flaws...
The premise of the flash is good: a flash-based version of Geometry Wars, an undoubtedly addicting game, yet its overall design is flooded with issues that greatly detract from its appeal.
The biggest flaw has to be the controls. Two things wrong here (both regarding movement). The first is that you decided to make movement controlled with the arrow keys. While this would seem to be the logical thing to do, it doesn't work in an ergonomical sense. I'm forced to use my left hand and put it on my far right (fyi, I use a laptop. Can't adjust the position of my keyboard to my monitor) because my right hand controls the mouse. This is just akward to use and I suggest that you reassign the movement keys over to the left, preferably 'WASD' style. Second, you can NOT move in DIAGONAL directions. In a game where evasion is the top priority, being able to move in more than four directions is paramount.
Those are my more serious issues with the game. Other minor issues regarded performance, and design. I currently use a dual core 1.7GHz processor which can easily deal with 99% of the flash products I've played. This game chugs, and for seemingly inexplicable reasons. I mean, c'mon, there's hardly enough action going on to warrant such choppy performance. If this game aims to be like Geometry Wars, then speed should be a primary factor in mind when designing such.
The sound isn't half-bad. The graphics aren't that bad either. The overall structure of the game is okay, and a revised version might just leave a better impression in my eyes.
I strongly suggest that you try to smooth out the stated problems, because I have a feeling that this could be an addicting game if said actions were done. Sorry for sounding so critical, it's only in the best of intentions.