Hi luckfont,
Thanks for the info. Unfortunately it seems like it's a problem with this specific hardware configuration - there was someone else with this issue who had the same set up. I have no idea why it's happening or how to fix it. Sorry! The only thing I can suggest is to make sure all drivers are up to date etc, and maybe try some different resolution settings in the pop up that appears when you launch the game.
Other than that it just seems like the game wont run properly on these 2011 macbooks :(
Sorry I can't be more help
Memory of God