Franchise Killer: Despite strong reviews on release, like many Wii U first-party games, it sold below expectations. Even with budget re-release and constant steep discounts, the Wii U version sold around 2.02 million copies by the end of 2020 according to 2021 CESA papers, a far cry from 5 million copies by Donkey Kong Country Returns. This ended up putting the series on ice for the moment; even though the Nintendo Switch port in 2018 generated interest in the game again, it still wasn't enough to warrant a new game on Switch, with the developer Retro Studios assigned to Metroid Prime 4 instead.
Milestone Celebration: The Wii U version was released in 2014, 20 years after the original Donkey Kong Country. Fittingly, the game features numerous nods to the original trilogy and has the Kongs celebrating the titular ape's birthday at the start.
Just like Returns, you can unlock Concept Art by collecting puzzle pieces. A lot of the concept art reveals enemies and stage ideas that never got implemented into the game itself.
Unused text in the game implies that there was going to be a Miiverse Achievement System for the game. The list also suggests that worlds two and three swapped positions at some point.
One piece of concept art◊ shows an unused idea for a minigame where Donkey Kong would be in a snowball fight against three of the Snowmads. Interestingly, one of them is an arctic fox, an animal that is not used in the final game.
Miscellaneous
Tropical Freeze uses a larger amount of original compositions compared to the previous game, but there's still a few returning songs. The returning songs are as follows, with the Tropical Freeze version's title first and the original title second:
From Donkey Kong Country 1:
World Map - Simian Segue (Would you expect anything else?)
Twilight Terror - Stickerbush Symphony. Additionally, the Staff Credits ends with a saxophone cover of Stickerbush Symphony performed by David Wise himself.
Frantic Fields - Original composition with riffs from Run, Rambi! Run! toward the end.
Additionally, the Rocket Barrel theme from Donkey Kong Country Returns gets a few remixes here, and the Golden Temple's theme (which itself is a medley of jingles and beats from the Donkey Kong Junior games) returns for the bonus world again.
in the game implies that there was going to be a Miiverse Achievement System for the game. The list also suggests that worlds two and three swapped positions at some point.
