The zip file was created on a non-POSIX system, so the execute bit isn't set on the executable. This isn't a *huge* deal, but it's just one more little step in the way of playing your game. I don't know which tool you use to create the archive, so you may need to postprocess it before distribution (or switch to a custom program for creating the archive with the appropriate permissions).
Also, I wouldn't mind a 64-bit version being provided as well, but that's much further down on the list.