This is a FlowGraph engine to fight against enemies NPCs in customs/multiplayers maps.
1) add the c2hunter folder into this path
c:\Program Files (x86)\Electronic Arts\Crytek\Crysis 2\gamecrysis2\Levels
2) execute crysis 2, go to mod menu, select and play "c2hunter" (you need the 1.9 patch to play this)
3) enjoy the game