SeriousSamClassic is open source game engine version developed by Croteam for Serious Sam Classic, but it should work on (or be easily portable to) any system that supports OpenGL 1.3 and SDL2.Note that while the Serious-Engine source code has been released under GPL, you still need to legally...

SeriousSamClassic-VK is open source game engine version developed by Croteam for Serious Sam Classic with Vulkan support, but it should work on (or be easily portable to) any system that supports Vulkan and SDL2.Note that while the Serious-Engine source code has been released under GPL, you...

ioquake3 is a free and open-source software first person shooter engine based on the Quake 3: Arena and Quake 3: Team Arena source code.The source code is licensed under the GPL version 2, and was first released under that license by id software on August 20th, 2005. Since then,our dedicated...

Yamagi Quake II is an alternative client for id Software's Quake II. Our goal is to provide the best Quake II experience possible, we strive to preserve the gameplay as it was back in 1997. Thus we aim mostly for bug fixes, stability and gentle enhancements were appropriate. Yamagi Quake II has...

Dhewm 3 is a source port of the original Doom 3 (not Doom 3 BFG, for that you may want to try RBDoom3BFG). It's known to work on Windows, Linux, macOS, FreeBSD, OpenBSD and AROS, but it should work on (or be easily portable to) any system that supports OpenGL 1.4 with ARB shaders, SDL and...

Sauerbraten is a free multiplayer & singleplayer first person shooter, the successor of the Cube FPS.Much like the original Cube, the aim of this game is fun, old school deathmatch gameplay and also to allow map/geometry editing to be done cooperatively in-game.The engine supporting the game is...