Since the release of the original Left 4 Dead in 2008, there have been a number of games co-opting its co-op gameplay while adding their own unique twists to the blueprint, including Call of Duty: Zombies, Payday, Warhammer: Vermintide 2 and World War Z. Back 4 Bloodis the latest release from developer Turtle Rock Studios, the folks behind the legendary Left 4 Dead and its sequel, as well as Evolve, the asymmetrical monster-hunting multiplayer game that never found an audience and whose servers were shut down in 2018.