In summary Create Games! works on Windows, Mac OS X and Linux - with several restrictions. Beforehand we must say that we do developing on windows 8.1-machines and porting the code result to other platforms. We expected more problems, but see:
Windows 7/8/8.1: No problems
Windows 10 (Build 9926): display errors in window-mode, no problems in fullscreen-mode
Linux (Ubuntu 14.10, native): Problems with sound and fonts
Mac OS X 10.10.2: Problems with performance and fonts
We think that these are rather minor errors that can be corrected until the beta. Remember: Create Games! is still in pre-alpha phase!