I just downloaded the game as part of that massive bundle. After I download the zip, I can't open or launch the game on my Mac because it's from an "unidentified developer" - any suggestions on how to get around this? 

Okay, so find it in Finder, then hold Control when you click it. Select Open, and then you'll have the option to open it. You'll probably have to do this with any app you download from the internet! Good luck!