Zombies and an additional 7 hours of gameplay for 10 bucks. Braaaaaaaaaaaains!
Borderlands may have been the surprise hit of the year in 2009. While I'm not a fan of paying for DLC so close to the release of a game, I can say that an extra 7 hours of play (co-op no less) for 10 bucks actually represents a pretty solid value these days.
There are new enemies to fight (zombies), though the main difference between them and the human raiders from the main game is that the zombies have no shields and tend to attack in swarms. (This make fire and blast elemental weapons particularly effective.) There are a few other new creatures such as the wereskags and some bat like creatures that take place of the flying rakk.
The new area (Jakob's Cove) is quite large, so much so that it was a bit dissapointing that you couldn't fast travel between the new areas that were in it. It doesn't appear that any new weapons or weapon types were added for this expansion (at least we didn't come accross any).
The humor from the main game is here, and is even turned up a notch with some laugh out loud moments when coming accross some of the characters.
If you enjoyed playing through the original quests, you should definitely pick this up, with the same caveat I'd give the full game; it's much more fun to play co-op online than alone.
Verdict: Buy it (or should I say, download it).
$49.99! Borderlands W/Free Shipping