One of the least mentioned yet most prevalent features of modern action RPG's like Diablo is the idea of the new game +. The basic idea of this feature is that after you beat a game the first time, you move into a higher difficulty playthrough, but retain your items and experience from the first one. Borderlands adheres to this trend beautifully, with a new game starting immediately after you finish your first run. The games are long as it is, and this simply makes them almost embarrassingly lengthy experiences should you have the inclination to continue shooting and looting beyond your first viewing of the ending - which is highly likely, given the addictive nature of the experience.