Simple, yet challenging; frustrating, at times, yet highly addictive, thanks to having only one life per game. Some others mentioned preferring that the ship maneuver via that arrow keys, but I like using just the mouse and needing only one hand to play this time-chewer. One thing I'd like to see in a subsequent version is the player's ship automatically firing without the player having to depress the mouse button, since there's no reason to hold one's fire in this game.
I managed to get all but two of the medals, and I don't imagine I'll ever score enough point to earn the "best-of-all-time" medal. I do wonder, though, when the "elite speed ship" is supposed to show up. As of this writing, I've managed to survive long enough to make it past 100,000 points and still didn't see it.