The expansion's missions revolve around a newly discovered vault that's been prophesied to open only when Pandora's ultimate badass spills the blood of a coward on its doorstep. Thus, Mr. Torgue sponsors a tournament of sorts to discover who that number one badass is.
Most of my complaints with the expansion can be filed neatly under "missed opportunities." As I played, there were so many times when I though to myself, "Why can't I do this?" or "Why didn't they include such?" or "It would have been great if…" And that's not exactly a good sign.
Here's the big one: many of the new enemies, including one new boss, are bikers, yet you don't get to drive a motorcycle around. Biker bandits speed by on spike-adorned choppers with equally deadly sidecars, and you're stuck in the same old Runners and Bandit Technicals. The "Captain Scarlett" expansion added sand skiffs, which were terrific fun—probably the best part of that DLC. So why the hell can't I ride a motorcycle around?
Elsewhere, there's a decided lack of worthwhile loot. The pirate DLC ended with a treasure trove that put even the original's "Secret Armory of General Knoxx" to shame. I'm still using some of the weapons that came out of that. But here, despite (*SPOILERS, I GUESS*) the vault opening at the end, the loot was only meh. And there wasn't very much of it.
And if I could just keep complaining for one more second, why is there no arena mode at the end? The story definitely leaves room for it. Maybe Gearbox thought because people complained so much about 'Moxxi's Underdome' that fans aren't interested in arena modes, but I believe they're wrong, and I was pretty surprised that one wasn't included in this DLC—especially given how short it is (with about five hours of new content).