We've all played zombie survival horrors in our past such as the Resident Evil series, Dead Rising and even "Zombies Ate my Neighbors!" but none of which instill horror and fun at the same time.
I am of course talking about Left 4 Dead, the newest creation from Valve.
Now, I'm a newcomer to Valve shooters (primarily because I never cared much for PC gaming in my younger years, which I fully regret) but I was impressed with the overall gameplay from all the Orange Box titles so I knew I was in for great things with this title.
The gameplay is still as smooth as Half Life 2 and Team Fortress 2, so this leads me to believe that it also applies to Counter Strike. You can navigate each level swiftly and effortlessly, creating a more enjoyable playing experience, and it also helps when running away from the charging infected.
The unique thing about L4D is what is known as the A.I Director. Basically a way to determine what will happen next in the game depending on your actions. If you're team is doing well, weapons won't show up where they should, and more hordes will spawn. As good an idea as it sounds, there's a limited number of ways the game can go, so if you're a long time player, you'll be able to determine the Director's next move.
Everybody loves co-op, and with this game being called Left 4 dead that is exactly what you can expect. A fully functional 4 player co-op over live (unfortunately only 2 player locally) for you and your buddies to dish out the street justice on the slobbering infected.

The game doesn't use a save feature for progress so completing a chapter requires sitting through from start to finish, but this is redeemed by the option to play any chapter you like, and any level within that chapter. Don't worry about leaving your game for any amount of time, as there is an 'Idle' function in your pause menu that allows the computer AI to take over for you, which CAN be handy if you have other matters to attend to, but NOT handy if you don't actually tell anyone and they don't notice.
You will notice an element of arcade style play here, from the likes of TMNT and Golden Axe. The 4 player co-op is the biggest giveaway, but also the death situation. Each player can lose their health whereby they become incapacitated and in need of reviving. While your character is in this state, another red health bar will appear and slowly deplete while you lie there and cover your friends from the ground with your pistol. If you happen to die, you will respawn inside a cupboard/small building which your team have to open to revive you. I thought reviving was a great feature to include, as it doesn't retract from the co-op element and ensures everyone can make it to the end of the chapter.
The infected are what you can expect from any modern zombie movie. They look dead, they run like athletes and they want your brain, but there's more the game than standard zombies. Known as 'Special Infected', there are bigger and more aggressive infected, complete with moves to make short work of you in no time. Keep an ear out while you're playing through and take caution when hearing the distinct screams/noises from the next room.
HORDES. Yes you've got to expect them, and thanks to modern gaming engines they are incredible spectacles. Hordes can be totally random, and they can be summoned by activating machinery or running into a Boomer's projectile vomit, leaving your screen a palette of soup, rendering you helpless and vulnerable.
If you happen to get caught in a horde, it can be quite daunting. They seem to get around you no problem, and circle you like vultures tearing chunks out of you. This makes quite a difference to the older zombie games where you could easily walk away from your enemies as they had no chance of catching up, but a refreshing difference at that.

It wouldn't be a Valve creation without a Versus mode, and L4D seems to deliver it quite well. The twist here is that the Versus takes place during a campaign, and 4 people play the survivors and the other team are the infected. Pretty traditional cat and mouse here, only with guts and guns.
It's great to actually see what the game is like through infected eyes, using their attacks and climbing abilities makes the Multiplayer what it is.
To round it off, Left 4 Dead is the ideal game for zombie survival fanatics and newcomers alike. The game has infinite replay value and most of all the game is FUN. Remember fun? If you want to take a break from standard First Person Shooters then load this up and have a good time. This game is some DLC short of being brilliant, and definitely worth buying and not just for a rent.
Thank you Valve, for just being you.