So I purchased Undead Nightmare for several reasons:
Reason the First: It's a very Halloween-y purchase and it fit with the mood over the weekend.
Reason the Second: I'm a bit of a sucker for zombies.
Reason...3: For only $10 (~800 points), you're getting a single player campaign. Sure beats the hell out of paying $15 for three new maps or new character skins.
Reason 4: Considering that my most favorite DLC in the last year was Ballad of Gay Tony and I love RDR a whole lot more than GTA...what wouldn't there be to love about this game?
Reason 5: You're not playing as Jack.
So far it's been a lot of fun. Life-changing...no, but FUH-UUUN!!! It's an aside from the RDR story and sets up with the Marston's spending some time in the living room with his kin before all Hell breaks loose. From that point on, you are basically running around New Austin saving people from the walking dead. This means bounty hunts are now rescue missions, each town has to be cleared out and helped in staving off the zombie hordes and strangers are still asking you to do weird and offhand stuff. Then there's the dilemna that Marston gets dropped into and must now solve.
It's very tongue-in-cheek which balances out the survival horror feel of the game. A lot of players have been complaining about a lack of ammo making it very SURVIVAL-natured. But if you take the time to fulfill your stranger and challenge quests, you'll be more or less okay. The zombies shuffle they groan and they even made several varieties of the zombies: bruisers, sprinters and retchers (so far). Each character from the original RDR campaign gets a nod in UN, some of them work really well in the setting (Seth, N.W. Dickens), some are kind of just there (Moone, the Armadillo shopkeep). But the best part is watching stupid rednecks as they try to figure out what is going on. They even throw in other supernatural creatures (Bigfoot, Four Horses of the Apocalypse). Don't know what else to say, don't want to spoil too much. It's definitely worth the $10, in my opinion.