Well, I have the same issue since last december or january, I believe.
I downloaded the game from this very site, installed it and start playing. Everything was fine until the last chapter, when I started getting this black screen when I launch the game.
I got so frustrated because I loved the game but I never had a chance to see the end of the story. I ended up deleting it, so my saves are gone, anyway.
Well, months have passed and now I got this e-mail inviting me to play 400 days. I wanted to give it a try and downloaded and reinstalled the game, but got the same problems. It sucks because I don't have a choice otherwise restarting my mac.
I know there are a lot of topics like that, but I tried some solutions and nothing worked so far.
Anything I can do?