Developer: id Software Release Date: October 10, 1994 Source Code Release Date: December 23, 1997
The retail sequel to DOOM eschews episodes for one long campaign of levels. Adding new weapons and monsters, DOOM II delivers on its promise of more DOOM.
If you haven't already, make a "~/Library/Application Support/gzdoom/" directory. Copy "DOOM2.WAD" from an existing installation of DOOM II into it. From here GZDoom.app should run and be able to find the data. If it can't, it will prompt you.
If you only have one WAD file, like "DOOM2.WAD", it will just run that. If you have any other WADs, like "DOOM.WAD", "TNT.WAD", etc., it will ask which one you want to run.
For more information on getting the game's data onto your Mac check our FAQ