As far as I know, it should just work. I'm not a mac guy so I don't know the specifics, but based on the number of downloads, and lack of comments about how it doesn't work, I'd suggest it's more to do with your system than it is about the game itself. Sorry man. Maybe antivirus blocking it? That can happen with renpy games sometimes.
I have no idea to be honest. Ren'py lets you just make a mac version, and that's what I've uploaded. I truly have no idea how games work on mac, but I assume there's some way since the mac version has been downloaded thousands of times, so I'd assume that if it didn't work I'd probably get more comments about this. Do you have any issues running other AVNs on your machine? It should work basically the same as any ren'py based game.