Man, I have this great idea for a new game. Hear me out. Alright, so we take some slow moving creature or monster, right? Call it a zombie. Now give them the numbers, alright? Lots and lots of them. And they can take a lot of hits. Now drop in some well armed humans that have to defend themselves against these zombies. Revolutionary idea or what?
Well, as it turns out, a lot of people have thought of this idea. And with good reason, as games such as Left4Dead show us. People like zombies and tend to also like hunkering down with some buddies to kill said zombies. It's a good combination.

It makes use of a "perks" system that I'm sure most gamers are aware of nowadays. Perks are more like classes in this game, and you advance each perk in an RPG-like fashion by killing monsters with certain weapons related to your perk. Each perk has several levels and many, many bonuses. As you advance your perks to levels 5 and 6 you'll start seeing some insane advantages, such as double clip size, close to 100% bullet penetration, as well as spawning with a gun that fits your class. It works well, and serves as an incentive to keep playing even in solo mode just to level up.

As an experience, KF leaves an impression that is fairly shallow. I found I couldn't play the game longer than a couple of maps at a time (usually amounting to 1-2 hours) and I took some fairly long breaks in between play throughs. I bought the game back at the start of the summer and I boot it up probably half a dozen times a month. It definitely has infinite replay value if you have some buddies to play with, but if you're alone you probably don't want to pick this one up.
One thing I appreciate is the DLC the game offers. It's cheap ($2 per character pack), unobtrusive, and serve as a great way to support the developer. Or not, if that's your prerogative. I personally have bought both character packs, largely because I can justify spending 4$ on a game I enjoy, but also because the characters are pretty cool looking.

It scratches some "itch" that games like L4D seem to miss. By boiling down the genre to basically the bare essentials and really polishing them you get a game that feels tight and focused. You know exactly the type of game you're going to be playing as soon as you boot it up, and that is definitely its biggest strength. Of course, if you're a gamer who doesn't like this sort of genre, then obviously you're going to want to look elsewhere.
Time Played: In total I've played this game for 80 hours since I bought it. I've played every map, every class, both online and offline.