Let me start off by saying this. Action game fans will be disappointed as there is more and emphasis on storyline and more cut-scenes than actual action(well not realyy but you get my point.) Rpg or adventure gamers more used to a deep storyline and stealth like action will have an absolute blast as I did.
First let me talk about the game characters. People going into this game thinking that you'll play the entire game as solid snake(like I did) will be sorely disappointed. There is a second character, while not as cool as solid snake, he gets the job done. This character has gotten universally panned on many game websites but he isn't as bad as people are saying. In other words don't let a fools opinion sway from buying or not buying the game. Buy it and form your own opinion.
Secondly let me talk about the storyline. It is as deep and as intricate as many major film releases and puts many others to shame. If your one of those people who had to see the Matrix twice to "get it" like I did. You'll need to play this game a few times and pay very close attention to every line of dialogue ever uttered in this masterpiece as you'll undoutedly be stumped by the many plot twists within the game, as they will leave your head spinning with amazement. The story is so good that it has a few thousand people posting theories on various parts of the game ,including the ending, on a bunch of different website messageboards. I mean good god how many works of fiction, let alone videogames, have had people posting theories on it. Bottom line great storyline.
Thirdly the second most important aspect of the game( the first being the storyline.) the gameplay. Many people will be turned off by it's dialogue heavey nature. They'll complain that you don't do anything. Well they can be happy playing games with a throwaway plot( cough Devil May Cry cough, great ACTION game though) but other people who enjoy a good story and great gameplay elements will love the game. There are so many memorable battles in this game like the fight against the new Metal Gear and a fight against a harrier jet that you'll want not only to play it again but collect all the secret items that go along with it. The sneaking around you have to do is so realistic it's scary at times. Another great new aspect to the gameplay is the ability to hold-up guards for their dogtags. Doing this allows you to colect secret items that give you the ability to become invisible(stealth to those "in the know") and the ability to have unlimited ammo. These game aspects encourage you to replay the game which gives this game ungodly amounts replay value, another game aspect that is important to me.
Bottomline anyone who wants to miss out on an awesome game experience just because you don't play as Snake the whole time or because you hate having to listen to storyline that puts many Hollywood productions to shame go ahead. The rest of us who enjoy great gameplay innovations and a deep plot will have quite possibly the greatest game experience of all time. And that's not a stretch of the imagination in any way.
Trivia: According to Wikia, Solid Snake has an IQ of 180 and is fluent in six languages and is the man who makes the impossible. possible!