Buggy?
The first time I tried I fired a lot of lasers and my computer froze up after 8 or so were on the screen. You should either put a limit on the lasers that can be on the screen at one time (Like a cool down period), or figure out why such small beams are eating up so much CPU.
Overall, the game idea could use some variety. Make ships that come and shoot at you, bosses would be nice too. Though I didn't play long enough to see if those existed, I assume they don't.