Maniac Mansion Cheats

At any time before Dr. Fred plays the fixed Meteor Mess game (meaning you have repaired the wires in the attic), you can enter 0000 as the inner door combination and the door will open. Presumably, the door combination is not stored in memory until the Dr. Fred Meteor Mess cut scene plays.

(Note: the Dr. Fred attempting to play Meteor Mess cut scene will not set the inner door code)

Exploiting this glitch will allow you to start the game with Dave and one other kid, instead of Dave and two others. To do it you must click on the kid you want to accompany Dave, and as fast as you can click on 'start'. If you've done it right, the 'start' button will become a garbled mess. Click on it again and the game will start, but you'll only have Dave and whichever kid you clicked on in your team.

When you enter Nurse Edna's room, quickly switch to a different character before she gets you. Wait for at least 20 seconds and switch back to the character in Edna's room. She'll just sit there until the next time you enter her room. This can be repeated as often as you like.

A similar technique is used to bypass the Purple Tentacle without the help of the Meteor Police, Weird Ed, Green Tentacle, or Recording Contract. Open both doors to the outer lab. If you're in the outer lab and then a cutscene (can be any one of them) occurs, the Purple Tentacle won't run after you and you get walk past him. To easily trigger a cutscene, either ring the doorbell (can only be done if Ed didn't get his package yet), switch to the kid outside the lab and run in there before Ed notices the doorbell's been rung. Or, if you have Jeff and/or Bernard have them fix the phone, call Edna, and before she answers it, switch to the kid outside the lab and go in quickly.

When you first go into the kitchen at the beginning, Nurse Edna is waiting there for you, and you have to outrun her or she'll get you. If you go the pause menu (where you can save, reset, etc.) and unpause, or switch to another kid and then back, she'll be gone.