Gearbox boss Randy Pitchford is astonished that Borderlands has yet to be copied by other developers.

"We're in an industry where people do nothing but steal from each other," said Pitchford, speaking to Gamasutra.

"I'm actually astonished that we're about to launch a sequel and no one's stole it from us," he continued. "The formula's right there. No one's stolen it yet. That's weird."

"Not that I want anyone to steal it, or I'm challenging people to steal it."

Pitchford later added that he felt conflicted during the promotion of the original game - wanting to attract attention to the project, while simultaneously protecting the underlying formula.

"When talking about Borderlands 1, it was really confusing, because on one hand we gotta scream from the highest mountain to get attention because it's a new IP. On the other hand, it's like, 'Shit, we don't want to tell people our secret because then they're all gonna copy it because it's so good.'"

Borderlands 2 will be out on September 21 for Xbox 360, PS3 and PC.