Discovered Doom mods. Brutal Doom and such.
At first for Ultimate Doom I own on disk, but then I looked into Freedoom Phase II, which is basically an open source project designed for modding and uses terrible graphics/sounds in the base game.
Cutting to the chase, I'm playing Doom 64, a mod that needs Doom 2 files.
People say Doom 64 is the best Doom. I never bought it, but now I do. It really is the perfect version, between the creepy ambiance, the monster placements, the challenge (You're walking along, and suddenly three flaming skulls charge right at you. Survive them, and a group of invisible enemies fires projectiles at you. Go ten more feet, and get your head ripped off by a giant monster out of view)