I'm not too familiar with Macs, so I had to look up some fixes for running Ren'Py-made games on the plateform. So far, I've heard that moving the game's folder into the Mac's "Applications" folder and opening it from there can get it to work. I also came across this fix tutorial (it requires you to download Ren'Py).
Let me know if it's still not working or if either of these methods work. I'm sorry about the trouble you're having with launching it.