The Last Bounty Hunter

Story-related and unmissable. When you get to the bounty board, select El Loco, play through his level, and kill/capture him. He will first poke out his shotgun around a wall to try and shoot you without looking, and he will miss. He will then come out and try again to kill you. Shoot the shotgun when only his hand is showing around the corner to capture him; shoot him in the chest when he comes around the corner to kill him.