This engine is the code behind "The game Creator's" FPS Creator development tool, A powerful, yet rough FPS engine.
Not bad by itself, but with mods, model packs, careful map design and many scripts you can create a great game with this software. don't be fooled by the seven year olds that make crap games.
the new updates are nice too, they added water, recoil, realistic ammo reloading and more. some of the model packs are amazing too.