Doh! Sorry about that. Thanks for the heads up.
I just tried running the latest build on my Mac and I was able to start a new game without issue, so there must be some sort of difference between our machines that's causing the issue. Do you know what version of OSX you're using?
I'm guessing there's probably an error printing out that would give me some direction on what's causing the issue. If you have a chance, can you try launching the game from Terminal and send me the full error message that prints out? You can launch it using this command:
open -W ~/Downloads/QuestionableMarkup.app
The "~/Downloads/QuestionableMarkup.app" in there is the path to the game on your machine. If you just downloaded it to the default OSX location, that command should work as-is, otherwise you would just need to update that last argument to path on your machine. If you have trouble with that, let me know and I can post a new build that will send the output to a log file instead (I've been meaning to do that anyways).