Cyclops:
Select "Config" at the main menu. Choose "Voice" and play the following options in order: 5, 60, 66, 60, 11, 60, 25, 60, 60. Cyclops will now by unlocked for purchase.

Cyclops Type-1:
Select "Config" at the main menu. Choose "Voice" and play the following options in order: 3, 39, 74, 21, 28, 43, 79, 82, 91, 61, 69, 32, 96, 25, 4, 66, 49. Cyclops Type-1 will now by unlocked for purchase.

Diablo Beta:
Select "Config" at the main menu. Choose "Voice" and play the following options in order: 89, 17, 8, 29, 31, 58, 93, 81. Diablo Beta will now be unlocked for purchase.

Diablo Tiger:
Select "Config" at the main menu. Choose "Voice" and play the following options in order: 2, 37, 2, 36, 2, 38, 2. Diablo Tiger will now be unlocked for purchase.