Follow the sheep
The single player experience is very unsatisfying and stinks of laziness and utter lack of innovation. I basically did not have to shoot hardly any enemies, and there is very little incentive to do so. Each time you reach a new area, a bunch of guys will show up all around you. There is no indication that they are friendly, except that their name appears when you target them. So by the time you find an actual enemy to shoot at, all the guys on your side will have shot most of them. Now that the script for that area has been completed (by the AI), you now proceed to follow some guy who has a yellow "follow" icon above his head. I spent the entire campaign just following some guy and never really had to try any tactics and didn't have to shoot hardly any enemies. It becomes painfully obvious that all the development time went into new textures (same engine though) and the scripted sequences which cheapens the experience and insults the consumer.
Another annoyance is, the game scripting will have the AI fighting you for covered positions. When ever I would finally get in a position I was happy with, the AI would come up from behind and push you out into the open and take your spot. I spent a great deal of time throwing grenades at my own guys to get them to leave the covered spots that I wanted to use. They almost immediately take the best spots when reaching a new area. It totally breaks the immersion and makes you feel like the game is playing you.
Last thing, they removed that awesome "swft" sound that the game use to make when you shoot an enemy. Now the only way you know that you've actually hit a human target is to spot their body falling using your scope, which obscures your vision and make it more a mini game than I would have liked to endure.
All in all, this is simply copy-n-paste game making at it's best and is very obviously targeted at making money off of the name sake instead of actually being a game.