Slow on a mac.
The main difference I've noticed between Flash games and so-called "real" games (y'know, for game systems) is that the heavy hitters are tested extensively. This game is really, really fun and would be addicting if it worked on my damn computer.
If you're on a mac, don't bother playing this game. The cursor is way too jumpy and that's if you can even get it to play in your browser. I got so many "you have another music-emitting flash window open" messages that I almost snapped.
Anyway, I wish more Flash authors -- this one included -- would test their games on multiple systems before release. Also, I wish it used the Newgrounds API so that we could have achievements. (At which point I'd switch over to my IE6 testing PC to play until I got all the medals... :P )