The Secret Armory of General Knoxx starts players off in T-Bone Junction. This small town is a rest stop on a sprawling stretch of highway raised above the dry basin of an ancient sea. In other words, it looks a lot like the other stretches of beautiful wasteland in Borderlands.
Players are required to drive a good distance along these roads to get to the surrounding areas, as there are no teleport locations. There are a few new vehicles, one of which is quite a bit faster than what appeared in the main game, but you'll eventually get tired of the extended driving segments that come with each quest. The four person Lancer allows crews to travel together, but it is slower and not much fun for two of the passengers.
Get past the unnecessary road trips and the rest is gravy. First off this add-on goes completely off the rails with wacky characters and some of the most inappropriately funny dialogue I've heard in a long time. Let's put it this way, one character hides her broadcasts behind an advertisement for a male enhancement drug. So whenever you receive a quest update you'll also get a pitch for a supplement called "Engorge."
You'll embark on the main quest in T-Bone junction rather quickly, and if you decide to focus on the story it won't take long until reach the end. But do this and you'd be ignoring numerous side-quests and entertaining loot hunts. As usual the road to your goal is guarded by an army of enemies that want you dead. The desert is filled with Skag riders, Atlas soldiers, and creatures that resemble giant waterbugs. Some enemies now zip around with jet packs or pilot giant mechs, adding a nice bit of variety to the combat.
The area around T-Bone Junction is filled with nooks and crannies, hidden treasures, and plenty of other reasons to explore. In my wanderings I stumbled upon an upgrade to the Lancer that allowed me and my friends to search for buried treasure across the desert. There's an arena, and a side quest boss that is seemingly impossible unless you and a few friends take the time to reach the new level cap of 61. Not only is the level cap extended, the weapons have a new level of rarity that you might be lucky enough to get your hands on if you destroy this monstrosity. All-told, this download will easily fill a long weekend if you take the time to fully explore it. It will last much longer if you grind enough to beat its most difficult enemies.
The level of difficulty on playthrough number one is perfectly suited to a player who only beat the main quest. But if you're thinking of trying this add-on on Playthrough 2, get ready to die... a lot.