PlayStation: The Official Magazine has revealed some more information on the flashbacks in MGS 4 that hinted at playable Metal Gear Solid memories in the game. …as characters talk and reference other stars of this universe, you may see an X or L1 button icon quickly flash on the screen. Hit the right button while it\’s highlighted and you\’ll be treated to a very brief context flashback. Basically, the system uses images and moments from the past Metal Gear games to help visually rekindle your own memories of the who, what, where, and why.