The entrance of Gruntilda's Lair greatly resembles the head of Gruntilda herself. Inside of her Lair is a large, maze-like structure constisting of various enemies, and gateways to other areas. It is largely cavernous but features some wild changes in environment (including a swamp, a snow-filled area, a forest and an enormous lava-filled chamber). Most of it is indoors, but the graveyard area where the Mad Monster Mansion entrance is to be found gives the impression of being outside.The pointy hat-like stone structure on top of the lair is actually a tower, which ultimately leads to the roof where the final battle against Gruntilda takes place.
Worlds Inside Gruntilda's Hideout
- Mumbo's Mountain
- Treasure Trove Cove
- Clanker's Cavern
- Bubblegloop Swamp
- Freezeezy Peak
- Gobi's Valley
- Mad Monster Mansion
- Rust Bucket Bay
- Click Clock Wood
- It is unknown if Gruntilda destroyed her old lair in Banjo-Tooie, or if the lair was destroyed after the boss battle of Gruntilda in Banjo-Kazooie.
- In Banjo-Kazooie, though after Gruntilda is trapped by the rock outside her castle, her laughing can stil be heard while walking through in her lair.
- In Banjo-Kazooie: Grunty's Revenge, a statue of King Jingaling's head can be seen laying on the ground outside Grunty's Castle. This could imply that at one point King Jingaling wanted to settle in Spiral Mountain with his people, but was overtaken by Grunty. This could have something to do with the dispute between Grunty and the Jinjos, and why she captures them in Banjo-Kazooie, and imprisons them in Banjo-Tooie.
- The first few bars of the theme music to Grunty's Lair sound very reminiscent to the famous song "The Teddy Bears' Picnic".
- Although they were separate game levels in the first game, the entrance to the lair was all the player got in the game's sequel, Banjo-Tooie and was then part of the Spiral Mountain level within the game.
- While the Banjo-Tooie version of the music track is similar to the first game, it no longer has the sound of a witch laughing in the background. This is due to Gruntilda's absence of the area in the game.
- When certain Game Shark or PAR cheats are used (which inadvertantly do something like violating protected memory or the checksum), the bridge to Gruntilda's Lair at the Spiral Mountain will have a large hole in it, making it impossible to cross without a levitation cheat. There are no still effects otherwise. Amusingly, the said bridge is in a similar state of disrepair in Banjo-Tooie.