Revenge Of The Cats: Ethernet is an independent purist, fast-paced, highly moddable, freeware, multiplayer PC FPS computer game. It is currently available for MS Windows and Linux-based operating systems. Revenge Of The Cats: Ethernet is licensed under the pretty restrictive Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License. However, all game content (scripts, textures, etc) is made available under the permissive Creative Commons Attribution 3.0 License.
Revenge Of The Cats: Ethernet
This looks almost identical to Tribes: Ascend by HiRez Studios.