There are several ways to trigger secret cutscenes in Metal Gear Solid 4: Guns of the Patriots. For instance, at certain moments during cutscenes a small X button may appear in the upper right of the screen, indicating that a series of flashbacks can be triggered if the player presses X repeatedly (these award Drebin Points). Also, during certain cutscenes the L1 button may appear, which will give you a first-person view through Snake's eyes. Finally, some of the cutscenes are more secret and only occur at specific points in the game. They can be found in Acts 2 and 4.

1. Act 2 - In the Research Lab, there is a cutscene with Naomi before the Haven Trooper attack. To unlock the secret cutscene, press the L1 button at two specific moments during the cutscene: the first is when she bends over to pick up Snake's cigarette and the second is right as she sits down in front of Snake.
2. Act 4 - After entering the Heliport, if there is no alert activated, a song begins playing. Head over to one of the security cameras in the area. There is one on the west side of the room and the other is in the northeast.
3. Act 4 - In the Canyon and Nuclear Warhead Storage Building, Otacon gives you a security code, which triggers a cutscene. Enter a different security code to receive 100,000 Drebin Points.