A quality game and probably the best in the series!.
Hideo Kojima has truly thought out the story well, and by looking at the differences from the previous versions, there is no wonder why MGS4 was delayed. This game is truly different from earlies releases. You have to be truly stealthy in order not to get caught by the militia men and PMC soldiers who themselves are fighting a war between each other.
You start off in a warzone in the middle-east. Guns are now ID Locked, so you have to use a stun-knife, until otacon provides you with an Operator and Silencer.
In thise game, the stages are more bigger, there are less places to hide and more enemies than ever. The only way to survive is to be truly stealthy. You are able to BUY weapons from a blackmarket gun dealer and unlock ID Locked guns and even sell guns you dont use. You can buy lasers, eye cams etc.
My favorite new feature is the camouflage which adapts to your enviroment, which is particularly useful when evading enemies. There is so much happening in this game, it's difficult to list all of them.
Now if I tell you more I will spoil it for you. See for yourself why everyone who is buying this game is rating it 10/10.