NowGamer - Score: 8,4
It’s number 13. Just follow the entrails up the stairs until you reach the clots... Despite (or maybe because of) being repulsive, festering meat bags, zombies have been en vogue for some time now.
Forget about cinema, which has been courting the walking dead in various guises for aeons, the games industry has only recently sunk its teeth into the genre and is now holding on like a bloodthirsty shambler. You can credit hardware and software technologies for this, at least in part: those extra CPU cores, ragdoll physics, damage modelling and graphics cards that resemble the Colossus’s little brother mean that developers are finally able to fling five dozen ambulant corpses at your monitor and treat each one individually, without sending your frame rate six feet under.

So the fact that Killing Floor is based on ageing technology and looks like Left 4 Dead’s budget second cousin has done it no harm. In fact, it’s done this zombie survival game a world of good, because when you couple old game engines with comparatively blistering hardware, you tend to be able to do crazy fun things with it that weren’t conceivable when the technology was built. Killing Floor started life as a mod for Unreal Tournament 2004, a popular one that weathered four years of playtime and hit version 2.5 by 2008 before Tripwire snapped up the licence, brought the mod team in-house and envisaged a better life for all as Killing Floor hit Steam as a standalone zombie abattoir.

Nipping at Left 4 Dead 2’s heels, it’s a perfect filler for those looking for a change but not a complete departure from Valve’s co-op survival horror. The fundamental difference here is that your priorities are skewed, so instead of legging it to safety and blasting any maggot sack that flings itself into your path, your primary objective is to obliterate each wave of undead and run to relative safety only when the odds are overwhelming, or you’re perilously low on ammo. This happens a lot, especially if you’ve selected anything above normal difficulty and short game length. With each wave the variety of the zombies becomes both more diverse and difficult: Clots are the bottom feeders with little else than power in numbers, Gorefasts resemble upgraded Clots with more mobility and bladed hands, while the limber and agile Crawlers represent the worst of the low-level vermin. Parallels with Left 4 Dead appear at this superficial level, too, with acrid bile-spewing Bloats and the Witch-like Sirens, whose piercing area-effect scream can swiftly disable you and comrades, making her a high-priority target. The final few waves will bring tough and deadly Scrakes and Fleshpounds to the fray, with a chain gun and rocket launcher-toting Patriarch as the ultimate boss.

Between each wave you get a breather, which on later waves feels like that beautiful respite between the painful sets of any hard anaerobic exercise. It’s more than just an opportunity to steel your nerves for the next onslaught, though, because Killing Floor’s resident arms dealer opens shop during this period to the tune of her cockney innuendo.

But chasing the perk level cap and the PC equivalent of Xbox Live Achievements is not the last word in Killing Floor’s entertainment value. As a six-player co-operative game it’s genuinely thrilling to play, even though with the current batch of six official maps and a tenuous DLC pack that gives you four different suits to wear, it is a little shallow.

In solo mode you’ll have your work cut out, even though the ‘killing floor’ itself scales the number of enemies to the appropriate difficulty setting for one player. With two or more players, you can afford to think more tactically beyond a shotgun and dual hand cannons. With an organised team of six the roles can be tailored very specifically to perks: a medic for patching the team up, a commando for welding doors shut and close-range shotgun duties, a firebug for annihilating hordes of Clots and softening up deadly Scrakes and Fleshpounds and so on. Killing Floor doesn’t do anything distinctive with the team dynamic that hasn’t been done by dozens of co-operative games in the past, but being the knackered sole survivor of a six-man team, with limited ammo facing the final half-dozen zombies while being spectated by the other five members, never gets old.

In fact, the Patriarch himself is a bit of a letdown, it’s the crescendo leading up to his entrance that makes it worth repeating all over again, and the knowledge that the penultimate wave of zombies will bring with it several dozen of Killing Floor’s most nightmarish denizens. And there’s something tantalising about the anxious wait you and your team endure, before the first few Clots of the next zombie onslaught shamble through the nearest entrance…