World Of Padman is a great first person shooter game. Initial release date was in 2007 and it has become very popular among the Linux community since then. World Of Padman works great on Windows, Mac OS and GNU/Linux. It is unique from the other FPS games and is open source. This is a cartoon style game that is very adorable and has awesome 3D graphics. A single player mode is not yet implemented but you can go into multiplayer and add some bots. Also, you can play offline against these bots or play online against other realtime players. There are plenty of different guns to choose from and many aesthetically pleasing maps. The game is fun, fast and addictive. If you want to see a preview check out the video here. Otherwise go to their website and download the WOP game. You will have tons of fun with this gorgeous first person shooter. Enjoy!