To unlock most of the pictures in the Museum, just start each of the main games five or ten times. Then, play each one for a few hours. Just leave the game idling; you do not have to be actually playing for that amount of time.

To unlock the playable endings, three movie trailers, and the last picture in the museum faster, change the day portion of the PlayStation 2's system date. For example, change August 25, 2005 to August 26, 2005. Then, start the game. Once you go to the museum you will have more playable endings and/or movie trailers unlocked. Repeat this process until you have all three movie trailers and sixteen playable endings in the museum. This will also get you closer to unlocking the final illustration.