The Xbox Series X and Series S are both fully backwards compatible with almost every Xbox One game. They can also play a lot of Xbox 360 and original Xbox games, too. That's a huge incentive for gamers who choose Xbox. Not only do they get the best Xbox One and Xbox Series X/S games to play, but they can also dip into a big library of compatible titles stretching back to the start of the 2000s. Plus, many of them are available as part of Xbox Game Pass.