Cybernoid

Unlimited lives:
Press  2  at the main menu to reconfigure the key commands.
Then, press  Z  Y  E  S (Left, Right, Fire, Fire) followed by  4  (Joystick).
Then, press  1  to start game play.

Unlimited lives (alternate):
Press  2  at the main menu to reconfigure the key commands.
Then, press  Y  X  E  S (Left, Right, Up, Fire) followed by  4  (Joystick).
Then, press  1  to start game play.

Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC command before running or restarting the program.
POKE 28870,165