Set in the immediate aftermath of the zombie apocalypse, Left 4 Dead's survival co-op mode lets up to four players blast a path through the swarming zombie hordes and terrifying mutant monsters. Guide your survivors across the rooftops of an abandoned metropolis, through rural ghost towns and pitch-black forests in your quest to escape a devastated Ground Zero crawling with infected enemies.
The catalyst for the popularity of zombie games, L4D provided the best blend of action, scares, social aspects, and pure replayability. With three distinct modes of campaign, versus, and survival, and with the addition of custom campaigns, it is a time sink for many hours with people online.
Graphics are still very good to today's standards, and the sound effects are superb with cues everywhere. The biggest plus for me was the various amounts of dialogue among the survivors, it makes each of them likable in their own way, and in some ways, relatable.
Controls are spot on, considering how basic it is. Very easy to pick up and play, with full access to the console commands as well (though some options of other Source games like fps_max are missing.)
Gameplay, while fun, has some odd moments that can leave something to be desired. The pacing is usually great (though the custom campaigns can be fatiguing) and AI Director does a decent job in changing things up for each playthrough. But, and this is a stinging "but", there will be moments where some oddities occur, like the hitboxes being off key. In addition, being a co-op based game, players will have to demand much from one another to pull through, on both the survivor and infected end, which is probably a tall order on the public scene. "Play with Friends" will be what Valve harps. The public community is not very kind, and with the release of a sequel, it has dwindled down. Still, very much worth it with friends, and with the custom campaigns out there, the simplicity of this game and the package it offers, there isn't much that this game can't provide for hours on end entertainment.