Primarily, Borderlands 2 is about looting and shooting (usually not in that order). The gameplay is immensely satisfying with the RPG elements, adding a great boost to combat and without the handicapping weapon training from the first game. Encounter a situation where you need to use a rocket launcher but you've been only using sniper rifles and SMGs to that point? No problem. Each of the character's special skills lead to a different style of play and are useful and fun to play with regardless of character build. Characters invest skill points in three different skill trees unique to their class. For example, the Assassin can be geared as a bada-- with a sniper rifle, gain new abilities with his hologram/cloak special ability, or be stated as a melee champion. Since you can potentially use any gun in Borderlands 2, I'd recommend grabbing what you can, comparing dollar values if you must leave stuff behind, and sort it out all at once after you've returned to a place where you can sell off the loot you don't need. Someone who stops and compares at every gun drop is going to be driven insane, because this game has more guns than the entire Call of Duty franchise.
I have to give the crew at Gearbox some serious props for their character design. I grew to like all of the characters in Borderlands 2, each of whom made me laugh at some point. The new additions to the cast are fantastic with Tiny Tina, the insane 13-year-old demolitions expert, being the most outrageously funny and Sir Hammerlock, the student of nature who really doesn't like it that much, being a personal favorite of mine. The game also reintroduces the player characters from the original Borderlands and fleshes them out in really interesting ways, making them an important part of the story without overshadowing the player character. The AI for these companions can be pretty atrocious at times, but, fortunately, they're unkillable and useful in a fight, though you may need to backtrack and find out what rock or enemy corpse they got stuck on to continue.
Borderlands 2 falls into the trap of being repetitive, but since the actions you're repeating are shooting things and collecting loot, it's right in many gamers' wheelhouses. If you're impatient, like me, there are a few side quests, which are frustrating because they require traversing and fighting through the same area you fought your way through not an hour ago in a main story quest. The other frustration I had was being one-shotted all the time. I mostly played as Zer0, the assassin, using a sniper build, which, granted, did make me a bit of a glass canon, but even with some serious shield and health upgrades, I sometimes found myself being taken out in one or two strikes. This was really frustrating if I couldn't find an enemy to kill to revive myself, such as during several of the boss fights, which I was then forced to restart. I'd really recommend playing co-op if you can, as having even a single companion changes the dynamic of the game, making getting knocked down or even killed in the middle of a fight less of a setback. Borderlands 2 has a great power curve dependent on the number of players, so while additional players change the dynamic, don't expect the game to be any easier.
The first Borderlands had a subpar story, consisting of a disconnected series of events, which somehow made sense to lead you to the Vault. Borderlands 2 does not have this problem, and it's all thanks to a man they call Handsome Jack. I wouldn't go as far as to say Handsome Jack is a great villain, but he is a good character who becomes the driving focus of the plot as he tries again and again to kill the player character. Jack's constant dialogue over the radio gave me a great impression of him, and as the game progressed, I became more invested in the mission to kill him. It's no secret the first game has a disappointing ending. So, does Borderlands 2 deliver? Without giving any spoilers, I'll say the game exceeded my expectations.
Presentation: 9.0, Story: 8.0, Gameplay: 9.0, Overall: 8.5