One of the reasons Pixar is so revered around here is that, as parents, you have to see a lot of movies you wouldn't normally see. So, when a kid's movie has the inevitable sequel that just phones it in, you just kind of grit your teeth and get through it. Bad enough to even have an Alvin and the Chipmunks movie, worse to have a sequel with the identical plot and a "well, they're gonna see it anyway, so don't bother doing anything interesting" attitude.
I said to The Boy after this, if it had been a sequel to Madagascar, we would've had the nerdy Bill Gates guy and his squid gun back, and the mom again, with the same Gru-trying-to-impress-her plot and on and on.
In a lot of ways, the central comic relief of these movies—the minions—is just a derivative of the little green dudes from Toy Story, but they've made them funny and with sort-of personalities and their weird little made-up language that make the execution unique to these films. This is good.
It's fine (even necessary) to steal ideas, the only real sin is just ripping it off and adding nothing. (As I've commented on "The Family Guy", I'm pretty sure they have, by this point, redone every gag in Airplane, often with no change.) This goes even when you're ripping off yourself.
Not to pick on Madagascar too much, but you know they're always gonna do that "I Like To Move It" dance, and they're always gonna have the "hilarious" old grannie punching out someone or something tough, and so on.
So, what's great about this sequel is that it's not any of those things. Think of a gag from the first one and you won't see it again here. The fierce dog? Well, he's there, but just a little. Gru's mom? Shows up at the end.
The girls' angst over Gru (and vice-versa) that was the central plot point of the original? Nowhere to be seen.
This is a great thing. Nothing cheapens characters like undoing the dramatic arc of the previous film so that you can reuse it in a sequel.
I doubt the Barbarian cared or noticed, even, though she did like the film a whole lot. (More than Turbo, less than Monsters U.)
The premise of the film is that Gru (Steve Carell, again doing his indeterminate Eastern European accent) is sort of down on his luck, because he's no longer in the super-villain business, and his efforts to repurpose his lab and minions to more productive ends has resulted in some really bad tasting jellies.
So he gets his mojo back, in a fashion, by working for the good guys in trying to capture a villain who has a nefarious plan for world conquest. He does this by going undercover in the mall with a quirky-but-lovely secret agent (Kristen Wiig). There, they settle on a Mexican restaurateur (Benjamin Bratt) as the likely villain, though there are some twists and red herrings along the way.
Russell Brand is back as Dr. Nefario, in a much smaller role. Moises Arias (Rico Suave on "Hannah Montana") plays the young latino paramour of Gru's eldest daughter (still played by the not-yet-skanky Miranda Cosgrove).
In summary: It felt like they were trying; it felt like they weren't so creatively bankrupt they had to lean on the gags and ideas of the original; there was enough detail to suggest a rich world with a long history, and to make some rather subtle jokes and references; and they gave it a new, dramatically satisfying story arc that's almost subversive in its conventionality (Gru needs a wife and mother to his girls).
As I said The Barb liked it, but so did The Boy and I.