Not much is currently known about the stage. The main platform appears to be the peak of Spiral Mountain. As shown in Banjo & Kazooie's introduction trailer, the plane of gameplay appears to rotate around the centre of the mountain, causing characters and objects on the spiral pathway to be pushed up the mountain. Additionally, a screenshot shows two wooden platforms on either side. Bottles, Mumbo Jumbo, and Gruntilda all cameo on the stage, with Gruntilda flying in the background on her broom.
Spiral Mountain is the starting area in Banjo-Kazooie and almost every other game afterwards. Banjo's house is located at the foot of the mountain, and Gruntilda the witch resides in a lair near its peak, connected via a rope bridge. In the first game, it serves as a tutorial area, where Bottles the mole teaches Banjo and Kazooie some basic abilities to prepare them for their adventure. The duo can explore around the mountain, find a set of Extra Honeycomb Pieces and some extra lives, and fight the mountain's living vegetation before heading into Gruntilda's lair.
In Banjo-Tooie, Spiral Mountain has been trashed by Gruntilda's minions just after her departure; many chunks of the landscape have been broken off and litter the ground. The bridge to Gruntilda's Lair is broken off, and its inside has partially collapsed; only the initial lobby, occupied by Cheato the spellbook, is accessible. The top of the spiral also has a Flight Pad, letting the pair explore more of its surroundings, including a waterfall cave.
In Banjo-Kazooie: Nuts & Bolts, Spiral Mountain is briefly seen in the intro before Banjo, Kazooie, and Grunty warp to Showdown Town with the Lord of Games. The duo return there for the final boss fight against Gruntilda, and stay there after their adventure ends.
The design of Spiral Mountain and its surrounding area in Ultimate is largely based on its appearance in the original game, as the bridge to Gruntilda's lair is still open. There is also some influence from its appearance in Nuts & Bolts, particularly with regards to its color palette.
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