6. Half-Life: Opposing Force - Don't Cross The Timestreams
Apparently Kojima wasn't the only one who was a fan of time paradox failure states. In the Half-Life expansion Opposing Force players were given the option to fight as Corporal Adrian Shepard, one of many US Marines sent to Black Mesa to kill all aliens and slit the throats of any witnesses. While proceeding to massacre a small army of the invading aliens, Shephard and Freeman briefly cross paths as the latter is teleported to Xen. If Shephard moves fast enough, the player can be rewarded by leaping through the open portal and following Freeman to Xen. He then misses the platform Freeman lands on entirely, plummeting to his death this game over message flashing across the screen: "Evaluation terminated: Subject attempted to create a temporal paradox." While Gearbox might have made a few changes to the lore while handling Opposing Force, they certainly retained the game's darkly sardonic humour.