Half-Life:Opposing Force takes place as your charecter being Adrian Sheperd. Arian is a Corporal in the army and is being trained for a mission. That mission leads him back to where Gordan Freeman was,yet not in the same places. During the game you once again see the G-man that just  appears somwhere and stands there clamly atching,then walks  away. Half-Life:Opposing Force goes to the places Gordan wasn't. You do not  fight on Xen anymore,butyou stay back on Earth and experiance what happend  while Gordan was gone. As the coporal,you command a squad of soldiers,but  you don't just start off with them. You have to find your friends for no  apperant reason. And the so called "Improved AI" i found  nowhere. During one point in the game you ahve a medic and and enginer.the  enginer opens a door and there is a drone gun waiting. Suddenly he runs  straight for the drone gun without shooting or anything yelling "We're  gonna kick your ass!".At that point he falls down dead because he has  just been pumped full of lead. Enemy AI isn't better at all. When you die,and  die again,and again ,and again you begin to notice patterns in EVERY move  the enemy takes. I got his game for Christmas,and beat it the same day in 4  hours using the meduim difficulty mode. That is how short the game  is. Half-life:Oppossing Force isn't a dissapointment though. It's a very good  game that should satisfy anyone that like Half-Life.