Metal Gear Solid 4 is the ultimate Metal Gear experience, so honestly, if you haven't played the previous titles, do so before picking this one up. Not because you won't enjoy it, you probably will.
After all, who doesn't like amazing graphics and good, varied gameplay? However, the story, the most essential part of Metal Gear, cannot be fully appreciated without having played the older games. Sure, the developers try to sugarcoat things with short flashbacks, but if you're new to the series, these won't help much.
Graphics
Huge, varied environments with tons of soldiers and robots chasing you through destructible environments. The real-time cutscenes are state of the art as well, the character models are especially superb. Hardly gets any better.
(10/10)
Sound
The good ol' cast returns, with a few new faces. So the voice acting is, as always, top notch. While on the batytlefield, you will hear gunfire in the distance, shells going off, everything. If you have a 7.1 surround system, you're in for one hell of a ride. Add to that a score by Harry-Gregson Williams, and you have audio perfection.
(10/10)
Gameplay
You can sneak, as Metal Gear veterans already know, and this approach is a good as always. However, if you choose to go out all guns blazing, you still have pretty good chances of making it through. The gameplay is extremely varied, and everything on the battlefield can be interacted with. The boss battles are an experience in themselves, especially one fought in a certain mech we all know and love...
(10/10)
Story
This is the last chapter in Snake's story, and all the loose ends have to be tied up. This means it will be confusing for newcomers, but this isn't supposed to be a newcomers game. This is a game for the fans of Metal Gear, those who have followed Snake from the wilderness of Alaska to the Soviet jungles. The story is full of surprises, and you're never bored. Look forwards to the final, FINAL cutscene. It's mindblowing, in a lot of ways.
(10/10)
Longevity
This is a game that can be played again and again. There are so many angles you can approach it from, so many routes to take, items to find and strategies to employ. Don't expect to stop after the first playthrough.
(10/10)
OVERALL: 10/10
This is what every fan has been dreaming of for the past 20 years. Snake's final story is also his greatest, and something everyone who calls themselves a fan should experience.