As soon as Banjo and Kazooie enter the doorway to this world, their greatest fears come to life as they encounter living gravestones, skeletons, and Gruntilda's haunted mansion. Mad Monster Mansion is the seventh world accessed from Gruntilda's Lair in Banjo-Kazooie. It is also the smallest world geographically in Banjo-Kazooie. However, it is one of the most difficult and complex.
When Grunty is kidnapping Tooty, this stage's music can be heard sped up.
The church in Mad Monster Mansion is modeled after the real church in Twycross (the home base of Rare).
Mad Monster Mansion's entrance in the beta version of the game was thought to be opposite Freezeezy Peak, behind Gobi's Valley or in the water level raising room.
Because of the way the Flower Urns talk, people often mistakenly hear the pots say something else of vulgar nature. Rareware has mentioned that this is untrue and that the pots merely say "Thank you". Grant Kirkhope, the voice actor of the urns, confirmed this on a special episode of "Game Grumps", called "Guest Grumps", on Youtube.
Some portraits in this world featured the Pirate, Captain Blackeye who was the original villain for Project Dream before it became Banjo-Kazooie.
The sticker on the front of the Banjo-Kazooie game cartridge appears to be set in Mad Monster Mansion
The music for this level was originaly going to be in Project Dream under the title "Bully". Parts of it also were to be in the piece "Chase"
This is one out of two worlds where a small Spring Jump Pad can be found. The other being "Treasure Trove Cove". They were reduced obviously due space restrictions.
Coincidentally, both pads are found on top of a building. In MMM it is on the top of the church and in TTC it is on top of the lighthouse.