Grimrock

Hello all, I'm on a iMac; model identifier 12,2; intel core i7 3.4 ghz; 4gb memory; amd radeon hd 6970m; mac os 10.6.8. I'm able to start the game fairly quickly (the gear pops up in less than a second) and can start a new game, get through the cutscene, and all that. Once in the first level, though...