Argos no juujiken (アルゴスの字剣)

Invincibility
When the "SEGA MARK III" appears, hold DOWN+RIGHT on controller 1 and UP+RIGHT on controller 2 until the sword appears in the opening screen. Now, when you start the game, your character will be invincible.

Check-point continue
Normally, when you use the continue option, your character appears at the start of the stage. With this code, you'll start at the check-point of the stage. Just select the Continue option while holding DOWN on both controller 1 and 2.