Cheat mode: 
Press [Esc] to pause game play. Press C and type one 
of the following codes at the password prompt to activate 
the corresponding cheat function. The word "Outstanding" 
will be spoken to confirm correct code entry.

Effect                       Code
Maximum fuel, armor          13593 
Invincibility                14214 
Mission select               17357 
Maximum weapons              25245 
All missions completed       33124