While there are many open-source games available (just see the recent discussion about the most advanced GPL-ed FPS), most of them are based upon the ioquake3 game engine that in turn is based upon id Software's open-source id Tech 3 engine. There's also games like Nexuiz that use the DarkPlaces engine and then also Warsow that uses QFusion.

Gregory Ray, lead organizer of LivingArcana.com announced today that he has hired the Brazilian programmer, Gutemberg Ribeiro, of “Conceptus” an open source game engine, to port his engine over to Apple’s iPhone platform. The port of the game engine will remain open source and will be available under LGPL license to allow true 3D game development on the iPhone.

Nexuiz is one of the most popular shooter games which emerged after the open-sourcing of the Quake 3 engine, featuring a fast-paced game style and several game modes, like the popular DM or CTF. Nexuiz is a free, GPL-licensed, first-person shooter developed online by the Internet-based team Alientrap, and it comes with ports for Linux, Windows and Mac.

World of Padman is an open-source, cartoon-style first-person shooter game available for Linux too, besides Windows and Mac. It is a wonderful standalone game based upon the Quake 3 engine.

Based upon the Cube engine, AssaultCube is a fast paced, first-person shooter, (partially) open source, cross platform game. Formerly called ActionCube, this game can be played both online with hundreds of other players from around the world or in a single player mode.

Since the release of Nexuiz 1.0 in 2005, we have been tracking its progress as one of the leading open-source first person shooters. With time, this fast-pace game has picked up a nice level of artificial intelligence for its in-game bots, engine optimizations, single-player campaign missions, and a variety of technical advancements.

Nexuiz is a free, open-source First Person Shooter running on top of a heavily modified Quake engine. It's a fast-paced game, where players combat online in large-scale battles or pit against witty-tongued bots in a progressive singleplayer mode.

Kris Occhipinti is currently in the middle of creating a 2D game created using the Blender 3D game engine. The game, called Pissed Off Penguins, looks similar to the popular “Angry Birds” game most of you have likely heard about. I wanted to outline this open-source project and expose some of the unique techniques Kris is using to both fund this project and create the game itself.

If you love first person shooter games then you will enjoy Nexuiz. It is a fast paced game. The graphics are very good. You have a lot of weapons to choose from and can blast anything you see in sight.