I bought this game from the Mac App Store a couple of months ago and just got around to trying it out. I was disappointed that it seemed to crash every time I tried to start a new game. I decided to play around with the graphics settings and discovered that if I set it on "Very Low" it played just fine. Afterwards I decided to experiment with the settings to figure out which settings are causing the crash. After some testing I discovered that the problem seems to be "Shader Quality". If Shader Quality is set higher than "Low" it will crash. I changed the settings to Ultra but turned down Shader Quality to Low and it still played fine. I will be going with the recommended settings but with the Shader Quality set to Low.
I hope this helps
(EDIT: I had originally said it was Shadow Quality that needed to be changed but it is Shader Quality. Post edited to reflect the change)