“Kampf” means “battle” and can also have, like in “Mein Kampf”, the metaphorical meaning of “struggle”. “Krieg” means “war”. E.g. WW2 is Weltkrieg 2, not Weltkampf 2.
Having not played TWOM I don’t know which translates would be more appropriate. The GP is however most likely a joke (and not a bad one IMHO).
It about trying to survive in a city in a fictional country during a war (similar to the Yugoslav Wars). So I think that krieg is appropriate but I haven't taken German in nearly 30 years so I'm rusty!