From Ren'Py

Single-Directory Mac Application

This hasn't actually been tested, so it could be wrong. Check out Ori Ochi Onoe for an example of this in action.

The default Ren'Py distribution builder builds Mac applications like they were Windows or Linux applications, with the base directory files at the same level as the Mac Application. A more traditional Mac application would hide the base directory inside the .app directory. We support that, here's how:

1. Be on a Mac, or at least a Linux box. The Windows filesystem doesn't support the executable bit, and so if you unpack and repack a Mac zip on Windows, you'll lose information and it probably won't work.
2. Extract the mac distribution of your game. We'll assume you built the game "mygame", and packed it into a zip of the name "mygame-1.0-mac.zip". So when you extract it, things will go into "mygame-1.0/".
3. Create mygame-1.0/mygame.app/Contents/Resources/autorun . You'll probably have to go and right or option-click on mygame.app in order to browse into it. (If option-clicking does not work, removing the ".app" from mygame.app may allow you to open it like a directory.)
4. Copy everything from mygame-1.0/ into mygame-1.0/mygame.app/Contents/Resources/autorun . Obviously, you'll want to leave out mygame.app, and also any README files you want to keep.

That's it. You now have a working single-directory Mac application, which you can then zip up, put into a dmg, or whatever.

You might also want to change the icon, by replacing mygame-1.0/mygame.app/Contents/Resources/launcher.icns with your own icns file.