Oh, I think I just replied to your email
. But here goes the explanation anyway, in case someone else has the same problem.
It's Gatekeeper. A.k.a. Apple's shady way to keep their system closed and squeeze profits from independent and freeware developers.
Unless you turn it off in your system preferences (
more info), Gatekeeper blocks games and other apps from devs who haven't paid Apple. And it doesn't even tell you so or hint that you can simply disable it. It purposefully displays a misleading message that the file is broken and has to be moved to trash, while in reality everything's fine and they are just being greedy bastards.
The worst thing -- Windows is trying a similar thing with their "Smart Screen Filter". Soon, it will be impossible to release anything, even freeware stuff, without paying off some big corporation
.