This game has a prerelease article
At the title menu, select the "HI SCORE" option, hold Right and press A or B on the first controller. Instead of the "RECREATION SYSTEM V1.00" screen, the "DARKMAN CONTROL ROOM" login screen appears. In this screen, enter "DERMA" as a password. Now you can select any of the sublevels or boss shooting events as well as ending sequence.
Like many other games published by Ocean, there is a hidden version and copyright string for the music driver:
MUSIC DRIVER V1.0 (C)JONATHAN DUNN & OCEAN SOFTWARE
A small Darkman head, stored near the item graphics. An extra life, maybe?
A Nintendo logo, stored with the rest of the graphics for the copyright screen.