Alternatives to Serious Sam for all platforms with any license

Unreal Tournament

Unreal is a series of first-person shooter video games developed by Epic Games. The series includes: Unreal (1998); Unreal : Return To Na Pali (1999); Unreal...

Free Open Source Mac Windows Linux
Multiplayer Add a feature

115 Like
Xonotic

Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux. The project is geared towards providing addictive arena shooter gameplay...

Free Open Source Mac OS X Windows Linux BSD PortableApps.com
Portable Real time collaboration Add a feature

67 Like
Quake

Quake is a series of first-person shooter video games released by id Software. In the game, players must find their way out of various maze-like, medieval...

Commercial Mac Windows Linux Steam
No features added Add a feature

83 Like
Red Eclipse

Red Eclipse is a fun-filled new take on the first person arena shooter, built as a total conversion of Cube Engine 2, which lends itself toward a balanced gameplay, with...

Free Open Source Mac Windows Linux BSD
Multiplayer Single player Add a feature

32 Like
Overwatch

Overwatch is a team-based shooter where heroes do battle in a world of conflict. Overwatch feature squad-based combat with two opposing teams of six players each....

Commercial Windows
Integrated Chat Multiplayer Add a feature

18 Like
Warsow

Warsow is a completely free fast-paced first-person shooter (FPS) for Windows, Linux and Mac OS X, set in a futuristic cartoonish world where rocketlauncher-wielding...

Free Open Source Mac OS X Windows Linux Web
No features added Add a feature

27 Like
- Discontinued Development has been discontinued, as stated at https://www.warsow.net/forum/thread/17216/1 . Last version, 2.1, released in March 2016, can be still downloaded from the official website.
Cube 2: Sauerbraten

Cube 2: Sauerbraten is a free multiplayer/singleplayer first person shooter, built as a major redesign of the Cube FPS. Much like the original Cube, the aim of this...

Free Open Source Mac OS X Windows Linux BSD
Portable Add a feature

42 Like
- Discontinued No more updates since Jan 2013 : http://sauerbraten.org/ . 2013, like Alien Arena, noticed discontinued.
Wolfenstein

Wolfenstein is a series of World War II video games. The series includes: Castle Wolfenstein (1981); Beyond Castle Wolfenstein (1984); Wolfenstein 3D (1992); ...

Commercial Windows
Free to play Multiplayer Add a feature

12 Like
OpenArena

OpenArena is a community-produced deathmatch FPS based on GPL idTech3 technology. There are many game types supported including Free For All, Capture The Flag...

Free Open Source Mac OS X Windows Linux
Free to play Multiplayer Add a feature

30 Like
- Discontinued Development is not stopped but last version, 0.8.8, was released in February 2012.
Urban Terror

Urban Terror started as a realism based "total conversion" mod for Quake III Arena. Nowadays, Urban Terror is played using the free, stand-alone, ioquake3...

Free Mac OS X Windows Linux
Multiplayer Add a feature

27 Like
Painkiller

The game is inspired by such classic titles as Quake and Doom, with the emphasis on killing large numbers of monsters. The game is divided into five chapters, each about...

Commercial Windows
Multiplayer Single player Add a feature

8 Like
Blacklight Retribution

Blacklight Retribution is a fast paced, adrenaline pumping free to play first person shooter (FPS) based in a futuristic urban warzone. Blacklight Retribution provides...

Free Windows
Free to play Multiplayer Add a feature

4 Like
Digital Paint: Paintball 2

Digital Paint: Paintball 2 is a Paintball game that started out as a mod for quake 2 but then took on a life of its own as an open source fps game with a global player...

Free Open Source Windows Linux
No features added Add a feature

7 Like
Freedoom

Freedoom is a WIP a complete free content game based on the Doom engine. It's not an engine, but it's replacement game data with entirely original content...

Free Open Source Mac OS X Windows Linux
Portable Add a feature

5 Like
CrossFire

Cross Fire is a free online first-person shooter featuring persistent rankings and five game modes – including the exclusive stealth-action Ghost Mode.

Freemium Windows
Free to play Multiplayer Add a feature

3 Like