Super Star Soldier

Unlockable: Level Select and More
With the system turned off hold Run + Select. Turn on your TurboGrafx 16 and release these buttons. At the title screen press Left, II, Up, II, Right, II, Down, II, Left, I, Up, I, Right, I, Down, I. Next press I + II eight times. To finish, press Select + I eight times.
This code allows you to choose your starting level, difficulty level, width of the playing field and more.