Metal Gear Solid 4 Database

The MGS4 Database is a downloadable application for the PlayStation 3. It takes the form of an encyclopaedia, and explains every piece of Metal Gear lore from all seven canonical entries in the series.

A user can choose how to navigate the database: either alphabetically or by category. In the case of category, the entries in the encyclopaedia can be accessed from an alphabetical list, a timeline of the series' in-game universe or a relationship tree (exclusively showing characters and affiliated groups).

The database was released on June 19, 2008 on the PlayStation Store in North America and Japan. It was released on the European store one week later.

The database was the source of much fan controversy when it was first released, as it contained references to several events in the Metal Gear universe which had been ret-conned (such as the Snatcher Project), and even ret-conned certain events itself (such as mentioning that Raiden's memories from his time fighting in wars as a child were erased by Solidus Snake).

By default, the database locks all references to Metal Gear Solid 4 to safeguard against spoilers. In order to unlock this hidden information, the player must have a completed MGS4 save file (and player data file, to ensure the save file was not downloaded).