Someone very helpful linked me here, and this is fantastic but I am very much looking specifically for the links to these games:
Cave Story
Decent 1-2
Hexen 1-2
Heretic
Quake 1-3
etc...
Admittedly I am partially retarded when it comes to navigating forums, so I apologize for the laziness but I get terribly agitated skimming through exasperating how to's when I just want the goods.