After ten years in retirement, Banjo the bear and his breegull pal, Kazooie, have stacked on the weight due to wasting all their time playing video games and eating pizza. Their evil foe, Gruntilda (now nothing more but a skull) finally makes it back to Spiral Mountain to start another fight. Their feud is soon put to a stop by the Lord Of Games, creator of every game ever, who is sick of their constant bickering. Confiscating Grunty's magic and Kazooie's special moves, L.O.G. proposes a challenge of his own design - the winner gets the title deed to Spiral Mountain...while the loser gets to spend eternity toiling in his video game factory!
Banjo-Kazooie: Nuts & Bolts is a sequel to the N64 game, Banjo-Kazooie. Players explore the world of Showdown Town, which houses Mumbo's Garage - this garage allows players to construct any vehicle imaginable as long as it follows some simple basic rules - it needs an engine, fuel, and a seat for Banjo to sit in. Apart from that, anything from hovercrafts to planes to trucks to rockets to unicycles (and more!) can be created. Showdown Town leads to many more worlds, each created by L.O.G.. These worlds house challenges - it's up to the player to build the most appropriate vehicle for that challenge. Solving each challenge earns Jiggies, which are puzzle pieces used to open up more worlds and finally face off against Grunty herself for the grand prize - the deed to Spiral Mountain.
The game also allows players to compete online against fellow Xbox Live players, as well as exchange blueprints to their vehicles, video replays of their challenges, and in-game photos.