Playing on a Mac
Please bear with us when it comes to the Mac version of the game - none of us are Mac experts (and if you are, we'd really value your input). Some people have had problems opening the game on their Macs, and this solution has worked for many people:
Right clicking the application> Show Package Contents> Contents> Mac OS> (This file will depend on the game, so yours would be Sovereign)
Open Terminal and type "chmod +x" hit space Drag your file over to the terminal hit Enter
If you did this correctly the file image should have changed and the game should now launch correctly."
http://forum.unity3d.com/threads/153435-Mac-OSX-Crash-on-Standalone-Startup
Also, if you have a problem and need to send us your log file, this is slightly more complicated than on a Windows machine, and where you will find it depends on your operating system.
http://www.macworld.com/article/2057221/how-to-view-the-library-folder-in-mavericks.html
This explains it for one set of operating systems. And this one is for a different set of OS.