left 4 dead

Err I think its just a lot more polished.. theres a lot of seemingly simple things that finish it off well.. like - source engine has the ability to do perfect cuts between animation and ragdolls.. the animation thing is kinda more important, it lets zombies just run at you and jump over cars without stopping, which is kinda important given they literally run at you full pelt.. then theres the director.. so the spawns aren't handled by the map compiler, instead they designed a system which is constantly listening to events the players are giving off, like - how accurate they are, how much ammo and health they have yadda yadda.. then it spawns zombies automatically in non-determined spaces.. it will do things like spawn 100 zombies which all run at you.. or spawn some of the special zombies..

Theres even a vs mode where two teams take turns at being the suvivors, and the other team gets to play the special zombies.. the goal for the suvivors is to get as far through the level as possible, and see who wins..

There was a demo online but its been taken off considering people would rip the maps from the fullgame and distribute them to run on the demo, but its been awhile since I've played a game thats this addictive and fun.. and I've just bought:

fallout 3, fable 2, crysis warhead, gears of war 2, red alert 3, too human, far cry 2, little big planet.

Playing it on steam at the moment, gonna get the 360 version soon I think, headsets seem pretty common there..