Metal Gear Solid 2 is one phenomenal game that has survived the passages of time intact.
Cons: Graphics have aged just a little; storyline is incredibly over the top and might not appeal to everybody; Raiden not as good a protagonist as Snake and comes with whiny girlfriend in tow; much of the story is told through codec, and a lot of the game is watched rather than played.
The Metal Gear Solid series is one of the biggest flagship Sony exclusives, and for good reason. It's distinctive brand of incredible voice acting, numerous twists and turns in the story, and immersive stealth gameplay were well-established by even the first installment, but this is really the leap ahead for the series.
Many of the gameplay mechanics will be somewhat familiar to fans of Metal Gear Solid, but smoother. The most important distinction between the two is probably the AI in this game. The computer AI in this is miles ahead of the AI in it's predecessor - it'll notice and send guys to investigate if you tranquilize someone, they'll hear you if you get too close even if they can't see you, and they're better in combat. Another important change is that now, to aim your pistols and rifles, you can switch to a first person view, helping you to line up headshots or shots to the heart for instant deaths or tranquilizing. Metal Gear Solid 2 obviously doesn't include the third-person view added in the Metal Gear Solid 3 remake, Subsistence, but that doesn't really outdate it because the fixed top-down camera view worked fine for this game mostly due to the environment and because this game includes the radar from MGS. The gameplay in MGS2 is deep and immersive. You can probably go through the entire game multiple times before fully utilizing all the strategic abilities at your disposal, giving the game an incredible replayability. Shoot out the camera from afar, or use chaff grenades? Should you be more stealthy, or take a more aggressive approach and deal with the guards forcefully? Should you tranquilize them from far off, or sneak up on them and choke them?
The story in Metal Gear Solid 2 takes up a pretty solid chunk of the 10 to 15 hours the game will take you on the first go through. A lot of the game is watched rather than played, and all of the cutscenes are done in-engine. This could have been a problem, had Metal Gear Solid 2 not looked so incredible for it's time. Though the next sequel would improve considerably upon the same engine, Metal Gear Solid 2 still looks great and probably would have looked great even if it had been released in 2004 or so. The cinematic cutscenes look fantastic, with great animations (though the voices don't quite sync) and a story capable of backing up the kind of time that is spent on it. A lot of the story and gameplay instructions are also told through codec, which isn't quite as exciting as the cutscenes obviously, because it's just two talking heads and the text appearing on the screen. Thankfully EVERYTHING in the game is voiced so it's easier to bear, and you can speed it up if you just want to read it faster. A lot of Metal Gear Solid fans were severely disappointed (to say the least) when they found out that the protagonist for most of the game was not superspy badass Solid Snake but new effeminate VR-trained Raiden. I didn't mind Raiden himself as much, though he's not as cool as Snake, but one part I didn't like was that you also have to bear his annoying whiny girlfriend, Rose, over the codec. Though she is, as is everybody in the game, voiced absolutely superbly, she's simply an annoying character and makes the loss of Solid Snake tougher to bear.
The game also has an odd sense of humor and knows that it is a game, as you'll be able to tell when it goes crazy midway through. Despite some of the ultra-realistic elements of the series, it's not asking you to pretend it's real, and this helps add some humor to the process as a whole, as well as some odd moments near the middle and end.
I only just discovered the Metal Gear Solid series. While it's advisable for newcomers to start out with the relatively short first game, this game will be the one to give you the kind of obsession that will have you salivating for the next installment. There's little excuse not to have played this series by now, with the PS2 reduced to the price it's at, because it is one of the best series of all time.