Remember the part near the end of Red Dead Redemption when former outlaw John Marston... found himself in the middle of the zombie apocalypse? Of course, you don't. Rockstar San Diego has seen fit to address that little omission with a whole new single-player campaign: Red Dead Redemption: Undead Nightmare. If you ignored the multiplayer-focused DLC and have instead been holding out for some quality single-player action, this is what you've been waiting for. Undead Nightmare isn't as fascinating as Red Dead Redemption, nor is it as much fun. However, Rockstar clearly had a good time making this lengthy add-on. It delivers a long-overdue send-up of the beaten-into-the-ground zombie motif, but it finds all the right ways to make itself at home in the Red Dead universe. A word of warning, though: don't even think about playing Undead Nightmare before finishing Red Dead Redemption's story. If you haven't yet, I advise you to read no more of this review until you do. Once you do, go ahead and start up the download -- it's worth a good bit more than its asking price.

Undead Nightmare ostensibly begins near the end of Red Dead Redemption. John Marston, after doing the dirty work of government suits Edgar Ross and Archer Fordham, has finally returned to his wife Abigail and son Jack. (Oh, and that worthless lout Uncle, too.) Things appear to be going swimmingly for the dysfunctional family until Uncle comes down with a nasty case of undeath. John manages to put him out of his misery, but not before Uncle infects Abby, who in turn infects Jack. So, Marston does what anyone would do in his situation: he ties his family up, locks them in a room, and goes out looking for a way to help them. Unfortunately for him, about 99% of the population from West Elizabeth to Nuevo Paraiso has become infected as well. This means another trek through hostile lands for poor old John. Undead Nightmare doesn't tell a particularly engaging story, but it doesn't at all take itself seriously. It's a joy to see how most of the cast deals with the zombie apocalypse. Hint: They get their dumb asses killed -- violently.

With a name like Red Dead Redemption: Undead Nightmare, it goes without saying that you're going to be fighting some very different enemies this time around. No more gunslingers; you'll have to deal with hordes upon hordes of cannibalistic freaks. There are a number of different zombie types, but they won't surprise anyone who's played a Left 4 Dead game. Retchers projectile vomit and explode upon death, Bruisers charge at you with their tremendous girth, and Bolters scramble about quickly on all fours. How do you take care of these mutants? Shoot them in the head -- duh.

The addition of zombies doesn't only affect the solo stuff. Rockstar has added a new multiplayer mode called Undead Overrun. This "wave after wave" mode isn't original at all, but it just so happens to be narrated by someone who evokes memories of the late, great Vincent Price. That's definitely worth something to me. On the subject of multiplayer, there's a smaller non-zombie-themed addition to Free Roam called Land Grab. It's a game of "Hold Down the Fort" that can be joined by anyone in the Free Roam, but can only be initiated by someone who has Undead Nightmare.

Red Dead Redemption: Undead Nightmare certainly goes all out with the new theme. For starters, the menu sports a sickly green hue and the words are featured in a spooky-themed font. The music is subtly different, yet cues from Bill Elm and Woody Jackson's superb soundtrack can still be picked up by discerning ears. There's also a new track that cleverly mixes surf rock with Halloween-themed novelty music.

There are some new additions, as well as a few zombie-flavored twists. For starters, there are a few new weapons to add to John's arsenal. All the gear from Legends and Killers and Liars and Cheats is available for John to use, and the new Blunderbuss manages to one-up it. It uses the limbs of the undead as ammo and blows apart zombies who are clustered together.

There are also four new mounts to find and tame; specifically, the Four Horses of the Apocalypse. War is a scaled-down version of Darksiders' Ruin that sets enemies ablaze, Pestilence is nearly impossible to kill, Death tramples anything and anyone unfortunate enough to get in his way, and Famine only looks cool. Technically, he's supposed to have unlimited stamina, but that's true of all the horses. Whether Rockstar decides to fix this has yet to be seen. Oh, there's one more mount that you unlock at the end, and all I'll say is that he looks just as awesome as the other legendary steeds.

Red Dead Redemption: Undead Nightmare doesn't make too many changes to the "Rockstar Formula for Open World Games." You'll still shuttle John Marston around the map to mission givers and stranger encounters. Some of the missions are jaw-dropping for a multitude of reasons, but most of the diversions are standard for the genre. Instead of hunting bounties, you'll search for missing people. Instead of clearing gang hideouts, you'll cleanse graveyards. There are only a few significant changes, and unfortunately, most of them result in mild disappointment.

The first problem has to do with the scarce ammo supply. I'm sure this is supposed to give the campaign a survival-horror edge, but Red Dead Redemption's gunplay is too much fun to restrict. It would have been nice to see some live villains thrown in for good measure.

The second problem is a bit more serious, and it has to do with pacing. Each major town on the map has been overrun, and the townsfolk need John's help to survive. Each time you enter a new town, you must kill a set number of zombies in order to earn saving and fast-travel privileges. This might sound like fun at first, but it gets really repetitive really quickly. Worse yet, even if you save a town, it will eventally be overrun again. If you don't want to lose the town, you have to fast-travel to the nearest town, ride all the way to the besieged community, and bust a set number of heads.

If this last section seemed to be down on Undead Nightmare, rest assured that it's still completely worth a buy. This is in large part due to the amazing value you'll be getting for your money. A new campaign with some added multiplayer action for just ten dollars? Should be a no-brainer.