Finished it yesterday around 2:45 am. When we were starting out I was playing with someone 5 levels lower than me (28 and 33) and we were about to go for Baron Flynt. He got killed a lot by the Lance, and I had to either keep reviving him or tank the damage - as a Hunter. It did keep things interesting, though. At the end I was at level 37 and he was 36. Earlier I bought a lv 34 static revolver that shock exploded at every single shot, and those guardians were helpless against it. When I get a pistol ammo regeneration mod after that, it's completely unstoppable.
But uh, what actually happened at the ending? Spoiler: So the Vault opens, big giant monster comes out that's not unlike Half-Life: Opposing Force's end boss, you shoot it really hard and it dies. Vault closes, please come back in 200 years. Well, that's a bitter disappointment, seeing as the Destroyer didn't drop very good loot itself. I was at least expecting a few Eridian or Orange weapons, but nope. Okay, so Angel, who is either a person operating a Hyperion spy sattelite, or an AI, knows a lot about the Vault and that thing that was in it. She makes us open it and kill it, and then thanks us for our efforts. No idea how she knows all this about it, and what her motives or goals were. And then there's CL4P-TP, INTERPLANETARY NINJA ASSASSIN. Does anyone have a clue?