Black Screen on Launch

Decided to buy the game since it's been officially launched, but I can't play it. I'm running it from Steam on a Macbook. The game launches to a black screen, and then stops responding. No music, no menus, just a black screen. I've tried validating the files on Steam and reinstalling, but so far nothing has worked. Any help would be appreciated, I've been wanting to play this for a long time!