I just dnled the COD 4 SP demo. I've remember why I hate the COD series' SP so much. It's too painfully obvious that it's scripted. The point of the game is just to try to figure out where the triggers are, because killing enemies is 100% useless unless they happen to be in your way or are explicitly part of an objective. There's 0 leeway to do things the way you want. The lack of health makes this problem even worse. You have to be exactly where you're supposed to be when you're supposed to be there, and your actions have very little effect on the out come of the battle, yet somehow it's progress is entirely dependent on you getting to the right place. Raising the difficulty setting only increases the restrictiveness. I'm not complaining about linearity, I loved HL2. It's just that in CoD you aren't playing a game. You're just add libing in a carefully orchestrated play where everything around just waits impatiently for you to catch up. It's one thing for a game not to be tactical. It's another for you to have to follow a script.