http://www.netrover.com/~timt/cheats/c/cybernoid.html (Amiga Plus Extra No. 5/97, 05/1997)On the title screen, type "RAISTLIN" and then the 'SPACEBAR' for infinite lives. Press 'N' to skip levels.
If you define the keys 'Y', 'X', 'E', 'S' (in that order) you'll get infinites.