Serious Sam is a very old-school FPS, there's no proper plot to speak of as the enemy A.I. boils down to running at you, or if they happen to have a weapon it involves running at you while firing. There's no tactical aspect to speak of, no cover system, no regenerating health, nothing that makes it even resemble any of the cookie cutter FPS games that arrived after Halo. To make it clear, none of this is a bad thing, the game is fun, frantic, and surprisingly good fun in co-op, but to put it bluntly, it's old. This is the same exact game that was released nine years ago for the PC, and it shows.