List of extras in Donkey Kong Country Returns

As with other games developed by Retro Studios, namely the  trilogy, Donkey Kong Country Returns rewards players with a series of extra content once they complete certain tasks throughout the game, such as collecting all Puzzle Pieces, defeating a world's boss, or beating the game on Mirror Mode. The optional content comes in the form of images, music, dioramas and (only in the Nintendo 3DS version) cinematic video clips, and can be accessed through the "EXTRAS" section of a game file.

Diorama gallery
Dioramas are inanimate three-dimensional models logging various scenes from Donkey and Diddy Kong's journey on Donkey Kong Island, starting with the Jungle and ending with the Volcano. Each diorama is based on one of the eight main worlds; the conditions to unlock it are defeating the boss and collecting all Puzzle Pieces from the Key Temple level of that world for the first time. Unlocked dioramas can be viewed in their appointed gallery, and can be rotated and zoomed in or out.

Image gallery
The image gallery is divided into eight sub-galleries, each related to one subject, such as Tikis, bosses, or the various worlds of the game. Released during the development of the game, these artworks show various ideas that were accepted or discarded for the final product. A large part of the gallery can be gradually updated by collecting Puzzle Pieces, but some artworks require, for example, defeating the final boss or beating the game on Mirror Mode. The sub-galleries are as follows:
 * Critters 1 and Critters 2 Gallery – both galleries contain artworks presenting the many species that inhabit Donkey Kong Island, most of them malevolent;
 * Tiki Gallery – contains artworks related to the Tiki Tak Tribe;
 * Boss Gallery – contains artworks related to the eight bosses of the game;
 * Worlds Gallery – comprises landscapes and paysages on the island, or up-close scenes of the Kongs exploring certain parts of it;
 * Kong Gallery – contains artworks focused on the Kongs, their partners and their travels;
 * Golden Temple – contains numerous early ideas for the last level of the game, the Golden Temple; to unlock the entire gallery, all Puzzle Pieces must be collected in the Golden Temple;
 * Bonus Gallery – contains miscellaneous artworks; to unlock the entire gallery, Tiki Tong must be defeated.

Rows detailing concepts that were either partially used or had undergone significant changes are in white, and sections of completely discarded ideas are in light gray.

Music gallery
Part of the game's soundtrack is available in the music gallery, which contains eight music sets linked to one of the eight main worlds of the game. A set can be unlocked by defeating the boss of its corresponding world.

Movie gallery
The movie gallery allows the player to rewatch the game's cutscenes and is exclusive to Donkey Kong Country Returns 3D. Movies can be unlocked by collecting Puzzle Pieces in the first eight levels of the Cloud world, which is also exclusive to the Nintendo 3DS version.