Speaking to CVG, Gregg Mayles, head of design at Rare has confirmed that if you want to just get on and finish Banjo Kazooie: Nuts & Bolts in a reasonable time-frame, you'll be able to.
"The trick is not forcing everybody to play it for a colossal amount of time. So if people want to try and complete it in like 20 to 30 hours that's fine. If people want to then carry on, that's fine," he said.
Mayles added: "The player will be able to play it, collect a certain number of vehicle parts, build vehicles to get through the game and then finish it - but to go back and retry all the challenges to try and improve their rankings, and by doing so you unlock the very best vehicle parts."
More through the link.