The best game I have ever played!
The graphics in the game are some special with superb environments that make you believe you are in the various places that the story takes you. The characters in the game again look amazing with a couple getting much needed improvements from their last outing in MGS on the PS1 lol! The story is the most engaging I have ever experienced since the LOTR. The story does rely on A LOT of back story so if your not familiar with previous games then I would recommend playing those first or else a lot of the story will be alien to you. Most of the story is told through cut scenes that are lengthy on occasions but if your familiar with the MGS format then you'll be right at home. The gameplay is brilliant as now you can play either stealthily, all guns blazing or a combination of both.
The muliplayer element Metal Gear Online does take A LONG time to get going with all the registration needed. However once online it is quite enjoyable although I didn't enjoy it due the slow pace as I'm used to CoD4.
Overall I would say that MGS4 is out and away the best game on any console and I'm quite sad that there won't be another one.