Speaking to the Telegraph, Epic's Cliff Bleszinski discussed the development process of Bulletstorm. He noted that the game began as a cover-based, third-person shooter akin to Gears of War "but in a world that felt like you were eternally in a factory that manufactured sparks." Over time, the team came up with the leash and sliding, and changed over to the first-person perspective that we see today. The leash in particular changed the gameplay, with Bleszinski noting, "we realized people were playing with their enemies like a cat plays with a mouse before he takes it out, so we thought why not reward people for that, and so the points system came along."
Another interesting tidbit: Bulletstorm originally had campaign cooperative play, but it was eventually removed. According to Bleszinski, co-op killed the game's pacing: it "just broke down, and it was a situation where people would race through the game, ignoring the vistas and they wouldn't set up as many skillshots," he said. That's probably for the best, because we're not sure today's processors could have handled the profanity generated by another Bulletstorm character anyway.