All those fantastic 3D spaces in modern shooters and yet party-pooping reality insists that we can only stick to the floor or bump face-first along the walls in them. So three cheers for Prey, which marooned you in an alien spaceship that never reliably decided where 'up' and 'down' were - magnetic walkways running you along the walls, gravity switches clamping you to the ceiling, curling rockets around the surfaces of baby asteroids.
Like Half-Life 2, Prey is at its barmy best in multiplayer, as you blast players through portals from unconnected rooms, or get picked off by someone on a different plane that you only spot when your corpse falls gently up to the floor afterwards.
Prey is out now for PC and Xbox 360
Above: They're on the ceiling! Hang on a second - you're on the ceiling. Oh boy