Slooow Mouse?

[Mudbill]

I figure it's in-game. The cursor moves super rapidly, but the character in the game requires several sweeps to turn.

It might have something to do with how the game handles the system's sensitivity. There's no raw input option, so it's probably layered with OS X's. You can try changing the sensitivity in the System Preferences, but this does sound like a separate issue. I've had no issues with sensitivity myself. What OS X version are you using? Any background programs that might be interfering perhaps?