Personally I would rate this game an 8.0/10, and with MGO I would give an extra half point, so it's an 8.5/10 because it is far from having a minimal amount of defects to be considered a game in the realm of the Caliban hall of fame for videogames.
Of all the boss fights I only liked the last two with screaming mantis, and liquid ocelot.
*sigh*
I think Kojima, and Payton (I think that's his name) tried way too hard with this game, or at least they could have needed one more year, if not more, for polishing the game in terms of character gameplay mechanics, cinematics, environmental gameplay mechanics, more original boss fights, a better and strealined online registration system, etc...