I see. Well, I learned something new today! Then Crisis Force doesn't have the extra sound chip? What would happen to an Akumajou Densetsu cart on an american system? What is the difference between FM and PSG? Thanks.
While not as underrated as some of the other games mentioned on this thread, Little Nemo: The Dream Master for NES was a solid game with some fairly interesting level designs and music. G.I. Joe: The Atlantis Factor is another game that comes to mind. It was released in 1992 when the NES was no longer in the limelight and the 16-bit wars were already underway.
Faxanadu (and other xanadu games perhaps on older platforms) on the Famicom/NES was an immersive rpg/action trip accross some original landscapes and awesome tunes, although the jump mechanics felt a bit "too real". All the Wizards and Warrior games with my personal favourite.. IRONSWORD!