Hello,
I was going to check out GSB on Steam because I saw that it was available for Mac, but the only demo available was for PC. Is there anywhere that I can get the Mac demo? Thanks!
The demo for GSB is available from Red Marble games. Cliff (and thus positech games) only does the Windows distribution
redmarblegames.com/gsb.html
Great! Thanks. I’ll get to try out the game now 
No problem! It’s also available for Windows and OS X on STEAM (although the OS X version is only 1.46.1, and at the moment won’t work with the campaign mode)