Pizza Hut - Demo Disc (PSX)

Spyro the Dragon code:
Press Square, Circle, Square, Circle at the main menu

Invincibility and fly mode - Tomb Raider 3:
Hold R2 and press L1 + X + Square while playing.

Nikita Launcher - Metal Gear Solid:
First, get the SOCOM from the truck. Then, crawl into the air vent, turn around, and head back to the truck to find the Nikita Launcher.