The game makes you feel more like a soldier helping in a desperate battle whereas the original game felt like you were just stranded soldiers looking for a way to defeat the locust. Speaking of the locust, they have adapted more to being formidable foes than Gears 1 and react in a way to show you that they want you dead.
The A.I is definitely a big improvement and need to be as they can be inserted into the multiplayer matches where they must react like you and capture meatflags and hold hills.
Bots are a great addition to the multiplayer and allow those that don't have access to Xbox Live to experience Gears 2 multiplayer modes. New Modes include Horde, Wingman, and King of the Hill. In Horde mode, up to five players take on up to 50 waves of varying Locust which recieve upgrades every 5 to 10 waves. Its definelty a stand out mode in my eyes and a good break from some of the more competitive modes.
The Campaign mode is bigger and better, but also leaves new and old questions unanswered, especially towards the end. Overall is a great game to have in your collection and those who buy it new recieve five free maps from the original. 4.5/5