Dealing death, riding horses and dealing death while riding horses(did we mention Showdown 's sweet mounted combat?) will keep you riveted through much of the main story. There's plenty of other stuff to do - ride for the Pony Express, play Texas Hold ‘Em, mine for gold - in the form of side quests, but none of these activities deliver the same rootin' tootin' good time you'll experience within the main story. You'll want to tackle some of these anyway to up your RPG-inspired stats, but you'll long for the meatier story missions.
The original Gun was criticized for its short length, and Showdown does an admirable job of addressing this, padding the package with additional content that's not just tacked-on filler. Six, PSP-friendly "Quickplay" games offer a variety of shooting and hunting challenges that provide perfect pick-up-and-play sessions. And three ad-hoc multiplayer modes - Deathmatch, Golden Cross and Poker - are welcome additions, despite not being infrastructure/online compatible.