Donkey Kong Country Returns/Beta elements

These are revealed in the gallery by beating the game.

The Beach's original boss
The Scurvy Crew weren't originally going to be the boss of the Beach. Instead it was going to be a giant eel with a bandage on its face that was wrapped around a lighthouse (it doesn't have a name as its description only says Eel Fight).

Realistic Rambi
Rambi was going to look far more realistic, and it appears that he was going to have a small bird perched on his head.

Original Volcano Boss
The Volcano was going to have a large banana boss called Angry Banana that glowed red and spat fireballs.

Ferndozer
Ferndozers were giant robotic barrel monsters which never made it into the final version of the game. They are only seen in the art gallery and they were going to appear in the Factory area. According to concept art, it appear that Donkey Kong was going to control one via remote control.

Forgotten Levels
Concept art reveals numerous discarded ideas for levels which were not included in the final version of the game. There was going to be a level or level scenery called Beach Bridge which overlooked the sea and some ships. Another removed level known as Amber Tracks was a minecart level apparently situated in the Volcano or the Cliff. A Forest level called Treetop Village was going to appear; it would have been reminiscent of the treetop levels from Donkey Kong Country. A removed level called Dusky Cliffs was going to be part of the Cliff area; it resembled Crumble Canyon somewhat, except it took place at night. A level called Old School was going to be a Factory level; it would have taken place outside and it be made out of red pipes, Gameboys, NES controllers, and Game & Watch handhelds. There were also going to be more levels for the Golden Temple, such as Banana Coaster, Paper Cutouts, Wacky Blocks, Pudding Wonderland, Virtual Boy Tracks, and Crackers and Pudding.