Extra credits:
Play the Deep Scan game. A credit will be earned every two submarines destroyed. These credits will be transferred to the Dynamite Deka game.

Extra Deep Scan submarines:
Highlight the "Start" option for Deep Scan, hold X + Y + Z, then press Start.

Fast Deep Scan submarines:
Highlight the "Start" option for Deep Scan, hold X + Y + Z + B then press Start.