GPL licensed (43)

Heretic

First-Person Shooter, 1994
Shareware (installed), Shareware

Heroes

Arcade, 1998
Freeware (installed), Freeware, Update

Hexen II

Role-Playing, 1997
Playable demo (installed), System component, Playable demo

Hexen: Beyond Heretic

Also known as Heretic 2

Adventure, 1995
Playable demo, Preview, FAQ

Kaos

First-Person Shooter, 2003
Freeware

Linley's Dungeon Crawl

Role-Playing, 1997
Freeware (installed), Freeware, Source code, Freeware

Mirror Magic

Puzzle, 2001
Freeware, Freeware, Freeware

MULE

Turn-Based Strategy, 1999
Freeware (installed), Freeware, Source code

NetHack

Role-Playing, 1987
Freeware, System component, Source code

NetHack Plus

Role-Playing, 1994
Freeware

NetHack: Falcon's Eye

Role-Playing, 2000
Freeware, Freeware, Source code

NGE Nibbles

Arcade, 2003
Freeware (installed), Freeware, Source code

Open Quartz

First-Person Shooter, 2004
Freeware, Update

Ptakovina

Puzzle, 2017
Freeware, Source code

Pym's Daily Word Square Puzzle

Puzzle, 2025
Freeware

Rise of the Triad

Also known as ROTT, Rise of the Triad: The HUNT Begins, Rise of the Triad: Dark War

First-Person Shooter, 1994
Shareware (installed), Shareware, Game expansion, Extra, FAQ