The new retro collection Rare Replay doesn't just offer a large number of the Donkey Kong Country and Banjo-Kazooie studio's games; it also offers a window into games that never made it out in the first place. There are five videos of unreleased games, including a sequel to Xbox 360 launch title Kameo (shown above.)
To unlock them, you apparently have to play the collection extensively. But this is the age of YouTube, so realisitcally, nobody has to play it at all! And Kotaku, helpfully, has aggregated all of the videos into one post.
Anyone who works in game development is well aware that a huge number of titles (and features for released titles) never see the light of day. But in this case, it's particularly interesting given both Rare's reputation, and what games did make it out of the first-party Microsoft studio.