Borderlands 2 is a hybridized beast of mechanics, play styles and audience potentials, all wrapped up in one cel-shaded package (now with green!). The sequel builds upon feedback from 2009's Borderlands, tweaking many aspects of single-player mode, streamlining co-op skill sets and building new character designs, writer Anthony Burch and concept designer Scott Kester from Gearbox told Joystiq.

One of the most prevalent changes players will notice in Borderlands 2 is the skill-tree functionality in co-op mode. Instead of simply beating down enemies separately but at the same time, as often happened in Borderlands, there will be more synergy between each character's abilities, Kester and Burch said.

For example, the Siren's phaselock abilities have been fine-tuned to include the "sweet release" kill skill, which insta-heals every member of her party if she kills an enemy frozen in phaselock. Additionally, the Assassin can execute enemies in the Siren's phaselock relatively easily with his melee or sniping moves, and the Commando will be able to throw down a bubble shield to protect the entire team. The Gunzerker is nuanced as well, including a skill that ramps up the power in the last shot of his gun's magazine, and if an enemy is killed with an excess amount of force, the extra points are converted to health. He can also dual-wield any weapon, which is awesome for everyone. Except the guys he's shooting at.

Gearbox is focusing on the single-player campaign as well -- in the first title Pandora felt empty if players roamed through it alone, but Burch has put particular emphasis on providing a central, ever-present story in Borderlands 2, he said. NPCs will communicate with players while they travel the world, cut-scenes will advance the gameplay directly and the story will be more continuous, as demonstrated by the Roland rescue mission. If players fail the mission in one spot, the enemies leave for another location and they must be hunted down and fought again.

Kester and Burch call Borderlands 2 a role-playing shooter, and say the magic is in the balance between a Fallout-esque RPG and straight-up Call of Duty-style shooter. Different elements of the game will resonate with certain players, without having anything jammed down anyone's throat.

Gearbox takes fan suggestions seriously, Kester and Burch said, and while there is no crafting in Borderlands 2, they have added more personality to each weapons manufacturer and have made it more obvious when an item is truly rare or an improvement, as opposed to just cool-looking.

Borderlands 2 includes Steamworks, a feature the creators are looking forward to, and which makes matchmaking and playing with friends much easier, they said. Players will also be able to trade gear, or even duel with their gear on the line -- and the winner takes the whole lot.

Gearbox has no concrete plans for a beta run of Borderlands 2, and it would be extremely difficult to capture the feel of the entire game into a 10-minute demo, Kester and Burch said. The final game is set to launch on September 18 in North America.

Update: Anthony Burch doesn't want anyone getting any ideas, and has clarified that there won't be a maelstrom of cut-scenes that break up the gameplay, meaning "if you wanna ignore what people are saying and go sell stuff at Marcus' store, you're free to do so," he says. "The story will inform the actual nuts-and-bolts stuff you'll be doing in mission -- it won't be 'go talk to Roland' without any context, it'll be 'rescue Roland from the Bloodshots, and you'll be getting constant audio updates from characters all throughout your mission."

This article was originally published on Joystiq.