Zombie slaughtering fun fest!
The idea behind Left 4 Dead is a simple one, the developers wanted to create an enjoyable multiplayer co-operative experience, that had replay-ability. The theme was decided as part of this basic design idea - who doesn't like blazing away shooting hoards and hoards of zombies?
So how does it work? You pick a character, who all play essentially the same, but have different personalities and dialogue - there is no advantage or disadvantage to any of them. Then you join an online game, wait for some more players, then set off to escape from the zombie invasion - picking up and using firearms, pipe bombs and molatov cokctails to get through the hoard.
An interesting factor in Left 4 Dead is how critical team-work is. You can play a single player game without online functionality - where the computer plays the others, but I would venture to say it's impossible to beat the expert mode without a good team of players.
If three of the team get killed near the start, I would venture to say it is nigh impossible to get through the level, if you do - it will probably be down to luck more than anything else.
The game plays well, the enemies are well designed, especially the special infected. The levels flow nicely and the developers have used a clever technique to subtly guide you through the level using lighting effects.
Throughout the development process, hours and hours of play-testing took place on Left 4 Dead, some of which caused huge, game-spanning game mechanics. The solutions to the problems players came up with are well thought out and the result is a smooth, very polished feeling play experience. The story is discovered by listening for dynamically generated character dialogue - which varies depending on how well the team are doing, what state they are in, what they've seen and a random element.
There were going to be cut-scenes but these were omitted to aid replay-ability, how I feel they could have been left into the single player campaign at least to tell you what is going on.
There are other criticisms, Left 4 Dead isn't perfect. There are no melee weapons, there are sometimes lag issues and minor graphical issues. Overall it is a very polished product, but a product that seems like a test-bed, a bit of a develop as you go along thing...
There is already a sequel to this, which in some ways is more polished and accomplished product that took the critisms form this first game and implemented improvements. However many people still prefer the original, the setting seems more appropriate, and darker, the characters fit better with the zombie apocalypse film idea...
The DLC for Left 4 Dead if anything makes up for the lack of the main missing element in the main game - content. Really the first four campaigns are too short - and despite the excellent replay value of them - if you get into the groove with Left 4 Dead you'll find yourself wanting more - and that is what Crash Course and The Sacrifice provide. The Survival pack is a must, and you should download it as soon as you have the game - the paid for DLC, well... Play through the normal campaigns first, they don't add that much except more more maps.