Mac

Project Zomboid works great on a Mac, but only when not running in a browser as far as I can tell.

Playing without browsers

Create a file called ProjectZomboid.command and put this in it:

#!/bin/bash
DATA=$HOME/Library/Caches/Java/cache/lwjglcache/cloud.projectzomboid.com/ProjectZomboid;
java -Xmx1024m -Djava.library.path=$DATA/natives -cp $DATA/zombie.jar:$DATA/lwjgl.jar:$DATA/lwjgl_util.jar zombie.GameWindow

Save it and open Terminal.app (In /Applications/Utilities). Type this and make sure you leave a space at the end:

chmod u+x

Then drag the ProjectZomboid.command file from the Finder in the Terminal window, which will paste the path to it, then press enter.

Now ProjectZomboid.command can be started by double-clicking on it in the Finder.

This has been verified to work in this environment:

zombiepie$ /usr/bin/sw_vers
ProductName:    Mac OS X
ProductVersion: 10.6.7
BuildVersion:   10J869

zombiepie$ java -version
java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07-334-10M3326)
Java HotSpot(TM) 64-Bit Server VM (build 19.1-b02-334, mixed mode)