Maniac Mansion is a point-and-click adventure game, originally released for the Commodore 64 and the Apple II in 1987. It was later released for MS-DOS in 1988, the Amiga and Atari ST in 1989, and the NES in 1990.
A Note About the Walkthroughs
The following walkthroughs were written for the NES version, so there might be some differences in gameplay if you play other versions.