Enter these codes at the following stages to unlock the corresponding effect.

During Demo - Get a DUKE Message:
Press Start + Vulcan Cannon + Missile + Foto Sensor and stick Right.

Stage 1 - Get a Message:
Press Start + Vulcan Cannon + Missile.

Stage 3 - Get 100 Missiles:
Press Start and speed fast.

Stage 5 - Get a Message:
Press Start + Vulcan Cannon + Missile.

Stage 9 - Get 100 Missiles:
Press Vulcan Cannon + Missile and stick Right.

Stage 11 - Get 50,000,000 Points:
Press Vulcan Cannon + Missile and stick Left.

Stage 13 - Get a Message:
Press Start + Vulcan Cannon + Missile and stick Left.

Stage 16 - Get a Message:
Press Start and stick Down.

Stage 19 - Get a Message:
Press Start.

Stage 21 - Get 250,000,000 Points:
Press Start + Vulcan Cannon + Missile + Foto Sensor and stick Up.

Stage 23 - Get a Message :
Press Start + Vulcan Cannon + Missile + Foto sensor.