(From an in-game radio ad from an in-game weapons manufacturer)
"DID YOU KNOW 97% OF ALL LIVING THINGS ON PANDORA AREN'T EXPLODING RIGHT NOW?! THAT'S BULL****! BUY TORGUE!"

Why aren't you playing it yet?

Seriously though, HUGE improvement overall on the first Borderlands. If you liked playing as the Soldier you're gonna just love this (360º aiming, reclaimable turret ftw!). Or if you ever wanted to dual-wield any weapon combination. Or going stealth + several hundred % damage multiplier on your next shot. Or stucking your enemies' head in another dimension while you shoot their asses on this one. Or summoning a huge robotic bodyguard of doom. Borderlands 2 has something for everyone's tastes.

Why I didn't recommend it before is a good question.
Possibly I was too busy playing it to even recommend it.
Because... 4 characters with fully unique skill trees, guns with dinamically generated attributes (so the odds of finding two identical weapons are, not exaggerating, below 0.1%) and leveling all the way to lv 69!
That, in an overall enviroment that combines lolz with shooty violence.
Give me a reason to not play it.

A truly fun game, despite all the mean reviews it has.
As in most games, online mode has most of the best stuff, though it can be challenging due to the veterans present.
The AI can be insanely hard to beat as well, just set it to Hard difficulty.

And a nice, rare feature: Single system split screen. Up to four players, on one comp.