http://tcrf.net/Proto:Dr._Mario_(NES)

Have any of you familiar with Dr. Mario ever knew that the working title for this game was called Virus? Three prototypes existed under this title in 1989 and 1990 (including one for the PlayChoice-10 arcade machine). Later on, a third prototype existed but is now given the present name of Dr. Mario, but things still weren't finished yet.

~Ben