At any time on the intro or the title screen, type 'O.S. FRIENDLY'. The screen will flash green to confirm the cheat has been activated. This enables the same in-game keys as the original. NOTE: you can now select from 0 to 55 in the map selection room.
'F' -- Gives robocod some wings
'P' --- Gives robocod the plane
'B' ---- Gives robocod the bath
'C' ----- Gives robocod the car
'X' --- Go straight to the exit
'S' ------------- Save position
'K' -------------- Kill robocod
'M' -------------- Map selector
'RETURN' - Invincibility on/off
'F6' -------------- 50 Hz (PAL)
'F7' ------------- 60 Hz (NTSC)
'F9' ----------- Screen effects
On the roof before the first door pick up the objects in this order:
Tap | Apple | Earth | Hammer | Cake
Pick them up in that order (the first letters spell CHEAT backwards). You are now invincible for about 15 minutes.