Borderlands 2 main story is 20 to 30 hours long

From gameplay to weapons to storyline, Borderlands 2 is going to be massively larger than its predecessor.  Gearbox has not been shy in boasting about the amount of expansion and diversity they've added to the upcoming cooperative FPS action game.

Speaking to dealspwn, Borderlands 2 concept artist Kevin Duc emphasized Borderlands 2 is "expanding on all fronts."

That means expanding the story which Duc says is twenty to thirty hours long in just "main plot line" alone, not including any side missions.

"We've still got billboards that you can go up to and get missions from, and we're introducing NPCs that you can gain side missions from," Duc reassured. "Within the missions, you can decide how to finish your objective and completely change the world. You can block off entire areas for yourselves if you don't complete a mission, or complete it a certain way. You can decide who to turn your missions into, which gives you different rewards and options."

The improvements don't stop there, however.  Duc went on to say Gearbox has improved everything in Borderlands 2.

"Every system has been looked at and expanded upon. You know, we have this formula that's an 'FPSRPG,' so we need to improve the shooter side and improve the RPG side," he explained. "We have expanded build trees, build trees that have much more influence on the guns, much more influence in co-op. You know, what items are you picking? How does that relate to what skills you've decided to go down?"

Borderlands 2 is set to release on September 18, 2012 in North America and September 21, 2012 internationally.  To get a head start, you can pre-order Borderlands 2 today and assure yourself a free fifth class: the recently revealed Mechromancer.