What does this have to do with Valve's beautifully crafted little Left 4 Dead 2 zombie survival game - well, apart from having a goal to complete the 'campaign' playing is much more centred around having a great time with friends with only very short term goals in play. We are might be trying to survive the current map as wave after wave of putrid zombies shuffle, scurry and leap from every dark passageway. But getting to the next safe room is more like a respite than a completion of a game or goal and there is no progression of our characters, equipment etc. Like going out to play 'catch' here you could say we are just playing, but I think we definitely are in a game as well... This is quite a contrast to my zombie slaying in The Secret World which is much more centred on the journey, evolving and improving my 'status/level/power' in the game.
The game is very Valvish, which means it plays beautifully, lets us in easily and is dramatic, moody and full of just enough complexity to keep us enthralled and wanting more. We play on-rails enough to keep us on the move and embedded in the story and action as it progresses, but there is flexibility in the weapons, positioning, order etc that makes decisions important. Valve do a great job of making us all feel like we have done a good job if we manage to get to that next safe room, no matter how actually good at playing we might be. The level design (incl graphics, physics, music, clues, interactions, etc) remind me of Half Life 2 and their other games - fun memories there as well and it still looks superb for a 2009 game!
[Left 4 Dead 2 Concept Art via the official site]
Take a look at these concept art pieces to see some of the zombie variety, this really makes the game, encounters are unpredictable because of them and force us to change plans and adapt. At its heart this is a super game for hanging out with a few friends - it is tailor made for this with coop being such a laugh-fest.
Lastly here is some more concept art of the environments.
[Left 4 Dead 2 Concept Art via the Kotaku]