This piece of DLC for Borderlands added, shock of all shocks, ZOMBIES to the list of enemies to fight off. Surprising, I know. In all seriousness, though, the zombies actually made a worthwhile and fun addition to the game. Borderlands is full of a lot of enemies that fight you with quality rather than quantity. Bandits and Crimson Lance members use cover and will try to flush you out with grenades and the like. Skags are nasty, jumping things that attack in small groups and strike quickly. Zombies, by comparison, are slow-moving, stupid enemies that just overwhelm you with sheer numbers, which require a bit of a shift in tactics to fight effectively. The game also includes some variety in their zombies, including torsos that pull themselves along the ground and attack from below your field of vision, Defilers which spit L4D-reminiscent vision obscuring vomit at you, suicide zombies which explode up close, psycho and midget zombies that move faster and more erratically, and Tankensteins which look like a 1950s film version of Frankenstein's Monster and lumber around with explosive barrels to pitch at you in addition to bog-standard normal zombies. They spawn fast enough that surviving until, for example, a hand-cranked elevator gets to you can get genuinely desperate and frantic. The game's sense of humor is very much on display here too, as the villain asks if you want brownies, then remembers he's trying to kill you and other hilarious moments of ridiculousness. The ending also deserves special mention for breaking the forth wall and making you jump out of your skin and laugh at the same time.
RPG notes: As usual, spoilers all over the place. If you don't want it spoiled, stop reading. While this seems like a fairly standard "...and zombies!" kind of story, and on some level it is, there's some useful stuff in here that can be cribbed for other games. First of all, the corporation in charge of the area doesn't evacuate and instead sends in troubleshooters to resolve the problem. While we've certainly seen this before, it bears mentioning as a useful plot device for some kind of monster infestation. While the right thing to do is pull out survivors, the problem is that, well, monsters are scary. Whether it's zombies, aliens, killer robots, or something else, anything that can overwhelm a well-armed settlement is definitely going to be treated with a certain level of fear my those on the outside, especially if said menace has the ability to hide inside the "unaffected" population and/or reinforce itself my transforming them somehow. And speaking of transformations, the final boss battle is a great piece of inspiration every GM should use at least once. Follow up an anticlimax boss battle with a more powerful form of the defeated boss after they players are sure the boss is down and are in post-fight mop-up for an extra shot of tension and chaos.