Die Hard Arcade Expert mode: Highlight the "Die Hard Arcade" selection at the title screen. Hold X + Y + Z + B to begin game play with four credits and more challenging opponents. Extra credits: Play the Deep Scan game. A credit will be earned for the Die Hard portion of the game for every two submarines destroyed. Hyper Deep Scan: Highlight the "Deep Scan" selection at the title screen. Hold X + Y + Z and press Start. This version of the mini-game has more enemy submarines for greater difficulty. Credits earned in this mode can not be transferred to the Die Hard portion of the game. Hyper Deep Scan X: Highlight the "Deep Scan" selection at the title screen. Hold X + Y + Z + B and press Start. Alternate soundtrack: Highlight the Diehard Arcade selection at the title screen, hold X + Y + Z, and press Start.