Kojima's really outdone himself this time. You can tell he put his heart and soul into it, and it pays off. It not only blurs the lines between game and movie, but destroys them. While it will get criticism for it's lengthy cutscenes( the longest one clocks in at around 45 minutes) I take it as a good excuse to take some time to take in the excellent story.
The gameplay is just as great. While I didn't much like the overhead camera or the first person aiming of previous games, all problems are fixed, matching it with the greatest of modern stealth games.
The music is a joy to listen to. It's all well composed and fully orchestrated, and thanks to the in-game iPod, you can listen to your favorite tracks from throughout the series while you sneak your way through the game's five acts.
The ending matches the saddest movie I've ever seen( Marley and Me) in terms of emotion, and nearly brought man-tears to my eyes.
Goodbye, Snake. I will miss you.