Check this site here:
http://www.konami.com/gs/twinsnakes/official/flash/index.html)
It contains a 26 minute long twin snakes trailer! Spoilers galore... showing some of every boss battle, even the final battle.
Also, just so you guys know, Twin Snakes is a remake of the classic Metal Gear Solid, originally released for PlayStation in 1998, I think. It contained one of the greatest video game story lines... ever. Its like an interactive movie. Twin Snakes added in better gameplay, and drastically improved graphics. Not to mention, revoicing all the characters (same actors) and brand new motion capture cutscenes (as can be seen in the trailer).
Like I said, it has over 4 hours of cutscenes.