Namco Museum Classics Volume 4

Assault Plus game:
Enter the X-Room then press R1 +R2 + L1 + L2 + Up + Triangle. The screen will flash and a sound will confirm correct code entry. Go to the woman that appears to the right of the pillar until Pac-Man gets her attention (indicated by "!"), then press X. The woman will point in the direction of the pillar, which now has a "Assault Plus" sign. Press X when in front of it and the Assault Plus arcade game will appear.

Return Of Ishtar game:
Enter the Museum and go to the Return Of Ishtar room. Quickly press Right, Left, Up, Down, Circle. A hidden version of the Return of Ishtar game will begin.

The Genji and the Heike Clans: Escape From "Hell" Stage:
During the game, when you fall off a cliff, you will be transported to "Hell". While in Hell, do not kill the spider webs just yet - keep killing the green spiders and collecting the gems they leave behind. When you have collected 80 or more gems, go to the red "acid pit" and go straight to the center. You will have "bought" your way out of Hell. The old person will appear and say, "Even hell depends on money." You will reappear in the "Kyoto" stage, and the game will continue as normal.
Information in this section was contributed by Keith Smith.

Alternate introduction:
Hold L1 + R1 when the Namco logo scrolls past while the game is loading. The FMV introduction sequence from the Genji and Heiki Clan will be displayed.

Extra credits:
Press Select to increase the number of credits available in any game as many times as needed.

Change robot to woman:
Get the attention of the robot receptionist at the beginning of the game (indicated by "!"). Press Triangle to look up, then press X. Press Square to look down and the robot will now be a woman. Repeat this to change her back to a robot.