Borderlands' fourth downloadable add-on gives players the one thing the game has been missing all along--a proper sense of closure. Claptrap's New Robot Revolution adds new zones and a new main quest line that pits you against enemies new and old as you attempt to stop the friendly little robots from rising up and taking over the planet of Pandora. It's an appropriate amount of content for the money, and if you're at all interested in continuing to play Borderlands, you should certainly pick it up.
The New Robot Revolution takes you to Tartarus Station, a new hub-type zone where Hyperion representatives are attempting to stop the Claptrap--which they created--from taking over the entire planet. Since you and your treasure hunting posse are the most effective killing machines in town, you're quickly contracted to deal with the threat.
That threat has led to the robot forces infecting a lot of the standard enemies you'd normally find in the game, which translates to a lot of standard enemies with vacuum tubes sticking out of their heads. So you'll still fight skags, spider-ants, bandits, and even a few bosses, like a Trapped-up version of General Knoxx. You'll actually fight this new Knoxx twice, which is perhaps a bit much. The downside to all of this is that most of the enemies are new in name and appearance only, so the standard combat tactics of running backwards while shooting as much as possible still apply. You will fight actual claptraps, though, which can get a little tricky. The "Divine Wind" variants just sort of roll up beside you and explode, which gives you something new to worry about. There's also that boss fight at the end, which is appropriately dramatic and one of the cooler things to appear in any part of Borderlands.
The developers have also made the game's quests feel like they matter a bit more than they have in the past by adding more speech. When you take on quests, the characters you're interacting with give you a bit of a monologue about what they're asking you to do and why. If you're the "run to map dot and kill stuff" sort of guy, you can just take off, but it makes the other characters in the world feel like they matter a bit more, which is cool.
The catch is that it all feels a little short and it was released ahead of an upcoming patch that will increase the level cap by eight and rebalance the old content to account for players that may be as high as level 69. Playing through this DLC before the release of the patch made the whole thing feel a little hollow, knowing that I'd probably have to replay large sections of it to gain levels once it's out there. The patch is due to be released ahead of a Game of the Year edition of Borderlands, which is due out on 10/12, so if you're planning on playing this new DLC, I'd recommend you wait until that patch is available so you'll get more than a couple of bonus skill points.
But if you're absolutely fiending for more Borderlands, it's not entirely empty without that character progression. The new quests and areas, combined with a "best of" lineup of characters from the other DLCs and other parts from the main game make for a good, exciting mini-adventure. If you're at all interested by the idea of returning to Borderlands, Claptrap's New Robot Revolution is absolutely solid.