Rockstar has put out a gameplay trailer for Red Dead Redemption
that shows off the engine, physics, terrain and some of the storyline. It truly looks to build upon the GTA IV experience, only with a Wild West flair. It appears that there will be an even bigger gameplay area, more options and definitely more interactions (including a bartering system) and treasure hunting. You can also choose to be good or evil, which impacts your honor. Check out the trailer, it will probably make you start longing for this game to get here as soon as possible.