Alien Arena Alternatives

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 engine modified, which doesn't require Quake III Arena, in addition to being an add-on to id Software's...

Tremulous is a free, open source game that blends a team based FPS with elements of an RTS. Players can choose from 2 unique races, aliens and humans. Players on both teams are able to build working structures in-game like an RTS.

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 and clan management system.

Unvanquished is a free, open-source first-person shooter combining real-time strategy elements with a futuristic, sci-fi setting. It is available for Windows, Linux, and Mac OS X.

Dead Space is a survival horror third-person shooter video game for Microsoft Windows, PlayStation 3 and Xbox 360.

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 five levels long. The player's objective is to get through each level, from start to finish, by...

Top-Down Multiplayer Shooter More than just Counter-Srike in 2D! Accomplish new missions like capture the flag or domination! Use a huge arsenal of weapons and equipment including crazy stuff like portal guns, lasers, RPGs, turrets and much more!.

A Libre Multiplayer FPS Game built with Godot game engine and a fully FOSS toolchain.

Zandronum is a multiplayer oriented port, based off Skulltag, for Doom and Doom II by id Software.

Blacklight Retribution is a fast paced, adrenaline pumping free to play first person shooter (FPS) based in a futuristic urban warzone. Blacklight Retribution provides FPS enthusiasts with a massive arsenal of weaponry and gear ranging from bleeding edge side arms to massive...

CSPromod aims to incorporate the best of CS 1.6 and CS:Source in one, feature-packed version. With 1.6-style gameplay and Source graphics, we hope and strive to re-unite the CS community.

This is a standalone game!

A truly free and open source multiplayer shooter, no strings attached. Have casual deathmatch matches on various scenarios. Build your own levels with the ingame editor and assets that come with the game, or just play around and use it as a sandbox.