A rumor was flying around the internet that MGS4 would have 90 minute cut-scenes. Gamepro editor says this rumor is false.

“I’ve beat the game twice, and am the author of the forthcoming [GamePro] review,” Shuman said. “Ninety-minute-long cinemas in MGS4 sounds like an exaggeration. Like the other MGS games, MGS4 definitely has a cinematic quality. And yes, some of the cut-scenes in the game are elaborate and occasionally lengthy. But not a one, to my recollection, even approaches 90 minutes.”

Source: Gamepro