I was confused on how Munster Madness worked, but got some good clarification from Dwight. On code .91:
Three Stages (Complete an area, Get Jackpots, Collect Hurry Ups)
Stage 1 - Goal is to complete one characters area. Do this by hitting one of the seven characters' shots. (the number of shots to collect that character depends on the character). Completing one character gets you to Stage 2.
Stage 2 - Jackpots. Timed mode where you try to collect as many jackpots as you can. Once the timer runs out, you move to Stage 3.
Stage 3 - Hurry ups. A moving hurry up (left ramp, then right orbit, then right ramp, then left orbit). Each one is on a timer. If you collect all of them, or one times out, you are back to Stage 1.
NOW, with .91 code, when you start Munster Madness it spots Marilyn for you right off the bat, so you start in Stage 2. Then if you survive in the mutliball long enough, you will get through stage 2 and 3.
Now you are back to stage one and you will need to complete another character to advance to stage two. Since Marilyn is already completed, you have to go after a different character. So hypothetically Munster madness has 7 different sets of stages that you can complete. I love the rules of this mode haha.
I hope that helps clarify the mode.