Chmod +x is the terminal command to MAKE a file executable, so that terminal can run said file. I know its not an .exe FILE, but none of the files were set in this fashion cause the base files would tell Mac it can't run the app, compare this an older versions of this game they were already set. No need to go in and change every file to its proper extension. 

Make a file executable in Terminal on Mac

Shell scripts must be executable files in order to run. You can use the chmod command to indicate that the text file is executable (that is, its contents can be run as a shell script).

Unless the game is still running on 32 bit then you need to tell people who own mac that they physically cant play the game unless they have a specific OS.