Little improvements would make it perfect
Voice Acting: -/10
Now there's a lot of things to say. First of all, the overall experience is nice, it's one of those game that have a high addiction factor. The re-interpretation of the original navigation system makes the game more playable (i never liked the original control system, even if i always found it somehow interesting).
A little list of things that you could improve:
-Game graphics. They work fine but some little improvements could make the whole experience more enjoyable
-Hit area, this is the most importat thing to fix i think. Make the hit area the same shape of the object it is for (asteroids, bullets, powerups and player ship)
-Audio FX, those need a fix. I'd suggest some higher quality sounds, preferably short so that you don't have too many noise in high asteroids traffic situation.
-Powerup direction, as Sciotix sayd, having powerups going around in different directions would be more interesting than having them just falling around.
I'd also be tempted to suggest a lower powerup drop rat, but the actual just fits perfectly and make the game more addictive.
So, it works and it's nice, but with little improvements it'd just be perfect ;).
Ah, know what? Maybe an extra "original graphics" unlockable feature would be nice :)