A while ago an ArenaFPS was brought to my attention called Unreal Arena. The idea of this game was to pit Quake (3) players and Unreal Tournament players together, and to fight based on which either side (trait) they chose. Quake players (team Q), will have Quake 3’s vanilla physics movement (EG: strafe jumping), while Unreal Tournament players will have their wall jumps and dashing. Weapon and item pickups will also depend on what side they choose.
Currently, there isn’t much to see and only have a bare bones demo, but the game is actively in development. Documentation will be located in the Github wiki.