Type "fifthdimension" at the main menu, and use one of the codes below:
Result - Key:
Disable active codes - [F1]
Big paddle - [F2]
Single gun - [F3]
Double gun - [F4]
Missile gun - [F5]
Laser - [F6]
Level skip - [F7]
Suicide - [F8]
Protective beam - [F9]