World Of Padman is a great first person shooter game. Initial release date was in 2007 and it is a free game to download. It works on Windows, Mac OS and GNU/Linux. It is unique from the other FPS games and it is open source. This is a cartoon style game that is very cute and has awesome graphics. There is not a single player mode implemented yet but you can go into multiplayer and add bots. You can play offline against these bots or play online against other players. There are plenty of different guns to choose from. 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 WOP game. You will have tons of fun with this cute and gorgeous FPS game. Enjoy!