I'm really enjoying this game, it's original; kind of like Worms crossed with Drawn to Life? Anyway, I thought I'd note some things that I think might be specific to Mac OSX.
Once you hit the "Go 2X Window", there's no going back to normal size window through the GUI. The screen will go too big and you may not be able to see the menus. To go back to the standard window size;
Edit the Settings file;
NxWindowed = 2 <<< change this to 1
Use CRTL+o to save and exit
In Snow Leopard the file is located here;
cd /Users/<<local account name>>/Library/Application Support/Steam/SteamApps/common/Cortex Command/CortexCommand.app/Contents/Resources/Base.rte/
On a 15" Macpro, the best you can hope for is 800x600, the text is hard to read, but it's ok. I recommend a mouse, as trying to click and rotate is very difficult. This game is good, but I can understand, not everyone will like it due to some buggy gameplay, but if you don't take it too seriously, it's a laugh.