I bought Gish for my mac along with the other games in the humble indie bundle, and I've beaten it on all difficulties including ludicrous (but not easy), but I still haven't unlocked the level select mode (which you're supposed to get after beating it on normal). Also, custom levels don't work. I put them in the levels directory in the .app bundle, but they didn't show up in game.
The game says that it's version 1.53, the latest version, but from the very inactive Gish forums, I learned that apparently the custom levels bug for mac was fixed in a previous version. Has anyone else experienced this issue, or know a fix? I didn't post on the Gish forums because the last post is from a couple of years ago.