If it aint broke, there's no harm in tweaking it a bit to make it better, right? Well certain gameplay enhancements have been made to the latest in the franchise. Now set in 2014, weapons are ID tagged to specific soldiers, so that you can't use any old item you pick up off enemies unless you have it hacked, which is easy to get done, by Drebin, a war profiteer that will do it for a modest fee in Drebin points, easily acquired by the automatic selling of excess guns to him. It's a clever way of making sure that whatever enemies use, you will be staggered and slowly develop when it comes to the power of your weapons.
If you're coming to Metal Gear Solid 4 from the rest of the franchise, you probably know what you're getting yourself in to with respect to long cinematics and story extrapolation, and the amount in this game is certainly comparable to previous games in the franchise. Indeed, it seems like they've replaced the majority of the long codec conversations with well made cinematics but the problem is that there seems to be less game to be padded by these cutscenes, so they seem to be a larger proportion of the overall experience.