Gearbox Software’s hit shooter Borderlands came almost out of nowhere in 2009, selling close to 5 million copies worldwide in the three years since its release. No surprise then that Gearbox is in development for a sequel slated to hit shelves sometime in 2012, and IGN has a whole truckload of details on the upcoming installment from the series’s concept designer, Scott Kester.

Borderlands 2 will once again take place on the planet Pandora, but there are a lot of refinements being made to the way you’ll experience the old setting. For one, the game will feature a lot more variance in the look of the planet, adding snow and fields to the usual rockiness of the original, but there’s more to the world than just a change of atmosphere.

“There’s a lot more diversity this time around, but not even just in the environments, also the creatures that inhabit them.” Enemy AI is more intelligent in the sequel; you’ll see creatures “ripping things up and throwing it at you or just scanning the landscape and on the fly taking different pathways at you.”

In addition to Pandora itself, Borderlands 2 will feature a brand new ensemble of playable characters, eschewing the original four from the previous game. This is in order to better suit the deeper class system and skill-tree elements. Traditional damage upgrades and the like will be available but Kester noted players will have the ability to “modify their character’s behavior in more significant ways.”

“We’re really trying to make sure there’s a lot more depth for the more hardcore RPG player side. We wanted to make sure that even though you only had one action skill we were going to give you multiple ways to use that, more so than we did the last time.”

It really seems like Borderlands 2 is going to focus even more heavily on the weapons; different weapon brands are going to be a bigger deal and more distinctly so.

“The hardcore guys really understood the differences between a Jakobs and Tediore,” said Kester, and they plan on making everyone aware of just how big that difference is this time around. “

“We actually took all the guns we made in the last game and in all honesty we basically chucked those and we started again from the ground. We didn’t want to just re-skin the guns from the last game. Every single gun in this game is different from the last one […]

The system itself works relatively similar but now we have a lot more components to it. We can add a lot more variants. Sometimes they can just be purely visual like there’s a bunch of nails sticking out, but a lot of times that might add to the melee damage dealt with the weapon. We’re trying to make sure all the things we’re adding aren’t just there for show but there is gameplay to support them. We felt that the last game, an assault rifle kind of looked like an assault rifle but you weren’t sure what its attributes were going to be until you fired it. We’re really trying to make sure that that feels right even at a glance. It’s much easier to tell how effective a gun is going to be at this or that due to the amount of barrels it has on it or just the size of the clip. There’s still the tech effects from the last game too and some more surprises as far as that goes.”

On top of all the inner-workings being upgraded and revamped, Kester went on to address the story element of the next Borderlands, addressing the original’s unbalanced focus on co-op play and promising a better experience both for multiplayer and single-player gamers.

“I think statistically there were actually more people that played the game single-player just because that’s the nature of consoles right now. We’ve really made sure that the single player side this time is more satisfying.”

Most enticing of it all however, may be this tidbit:

“We’re trying to make sure that we’re not a cut-scene game, we’re not going to stop to tell you the stuff. We’re trying to integrate the story into the missions so as you’re playing you’re being delivered story, you’re being hopefully more engaged. The missions themselves aren’t so much fetch quests all the time that are just A to B, A to B. We’re making sure that those really propel the story forward.”

With all that in mind, remember Gearbox is still keeping their lips sealed on a lot of other content. Borderlands 2 is shaping up to be far bigger and more expansive than its predecessor, so if you’ve already experienced Pandora before (and I don’t mean the blue cat-people one) I’m sure you’re anticipating this one. I know I’m excited, and I never managed to get my hands on a copy of the first.

Borderlands 2 is slated for a 2012 release.