Killing Floor Hold the line, paint the walls red

The mission is simple: survive the waves and cleanse the area of the experiments. How you do it is up to you. The maps are open and non-linear, so you decide where to make your stand, and when running is the better plan. You carry a welder, and sealing a door can steer the whole horde down a corridor of your choosing instead of through yours.

You drop a specimen at the end of a hallway, then weld the door behind you while the rest of the wave looks for another way in. Between waves there is a short breather to buy weapons and armor before the next one arrives.

Everything is configurable: set the difficulty, the number of waves, even your own favorite lineup of monsters.

You pick a perk before the fight starts, and each one changes your role. A medic keeps the team standing, a berserker wades in with melee, and there are techs, snipers, commandos, firebugs and demolitions specialists besides.

The arsenal runs past 33 weapons, from knives and fire axes to pump shotguns, rifles and a flamethrower. Ten monster types come at you with teeth, claws, chainsaws, chain-guns and rocket launchers, so what you carry matters.

And when a kill lands just right, time slows down in ZEDtime to let you watch it, even in multiplayer.

This is a game made for six-person nights. Co-op runs up to six players against the waves, and the perks only make sense together: someone heals, someone holds the line, someone covers the flank. One mistake on higher difficulty can cost the whole team, so coordinating before the wave hits is part of the fun.

It is also a game with a sense of humor about itself. When the wave ends and everyone is still standing, that shared relief is the point.