Snake makes impressive return......
For starters, the game seems much more fluid than its predecessors. It seems much easier to play the role of an illusive operative than in the past, particularly when you consider the abilities of Snake's new suit. The game is also a pretty capable shooter; if you choose to go that route. Performing fancy maneuvers is a snap, and you'll feel right at home rather quickly. It's also easier to subdue unaware enemies, since the process seems to have been more simplified.
The interface is also pretty intuitive, and refrains from being obnoxious. If you've played the two previous games, you should feel right at home. The game also does a much better job of conveying the surrounding environment to you as well.
Other, intrinsic improvements include the behavior of enemy a.i. Enemies do a better job of flanking you, retreating to call reinforcements and generally doing their damnedest to kill "Old" Snake. It's enthralling watching them get suspicious by a barrel (that you happened to be hiding under) suddenly move to a different spot (even if they didn't see it move), or screen an area looking for you. For one thing, Snake doesn't seem as "bullet proof" as he did in the previous games, and retreating from enemies almost becomes a habit when you consider their lethality; especially at higher difficulty settings. Furthermore, the boss battles are excellent, and, like the previous games, require a lot of contemplation as opposed to an itchy trigger finger. The stamina bar also plays more of a factor due to Snake's age, which is a nice touch.
Another interesting aspect of the game is that it takes place in more varied environments. You'll go from a desert in the middle east, to a frozen tundra in Alaska. Graphics wise, the game is spectacular. In terms of the story, it is well presented, acted and highly memorable. In fact, it could be argued that you watch lengthy (and I mean lengthy!) cut scenes more than you actually play the game. But I thought their quality overshadowed this fact, and did good job of pacing the game. Others may not be so forgiving. You can skip em, but.....
Overall, if you own a PS3, you don't have an excuse not to own this game.