Donkey Kong Country Returns is notable for introducing entirely new antagonists, the Tiki Tak Tribe led by Tiki Tong, instead of reusing King K. Rool and the Kremlings, who were the series' primary villains since Donkey Kong Country. According to the game's producer Kensuke Tanabe, he and Shigeru Miyamoto discussed early in development whether or not to bring K. Rool back, but they ultimately concluded that it was unnecessary, leading Tanabe to ask Retro Studios to create their own new antagonists. The game's senior designer Kynan Pearson claimed that this was done in an effort to differentiate the game from the previous Rare-developed Donkey Kong Country titles. King K. Rool and the Kremlings would eventually return years later as Spoiler:surprise final antagonists in Donkey Kong Bananza. Pearson felt that the character's return was bittersweet for him due to Nintendo's original mandate when he worked there, while also feeling that it allowed for K. Rool's appearance in the game's climax to be more effective.

In an interview with Nintendo Dream, director Kazuya Takahashi revealed that the team had initially considered using Pauline's adult design for her appearance in Donkey Kong Bananza. However, as they had wanted Pauline to ride on DK's back for the game, they redesigned her to be a child as the smaller size felt more natural for what they wanted while also reintroducing the character to new players unfamiliar with her.

Unlocking every skill in the game by collecting all 1000 Banandium Gems will change the appearance of the Red Balloons to be shaped like Donkey Kong's head. This is a reference to how Balloons originally appeared in the first Donkey Kong Country game, where they were also modeled after his head and granted at least one extra life.

The unbreakable tiled floor pattern at the bottom of the Freezer Layer's terrain includes Zebra hoofprints, reflecting the Zebra tribe that can be found in this layer.

In the Freezer Layer, the snowflakes that fly through the area are shaped like Zebra hoofprints, reflecting the Zebra tribe inhabiting the layer.

When deciding what characters would appear in the game, Nintendo EPD took inspiration from the original Donkey Kong arcade game, which established that Donkey Kong lived alongside humans. While the team debated how much human-related content and Donkey Kong Country-inspired elements would be included, producer Kenta Motokura mandated that the character Cranky Kong should appear because he was a fan of the character.

It was decided early on that another character would accompany Donkey Kong throughout the game, though no specific character had been included in the software design description. One developer suggested Pauline, with this idea being revisited following the implementation of Donkey Kong's "Zebra Bananza" form. The composer had written music for the transformation sequence, and the team decided to turn it into a song that Pauline could perform, having been established as a singer in Super Mario Odyssey. Both Motokura and director Kazuya Takahashi credited Pauline's inclusion with helping many of their ideas take form.

The inclusion of the character Pauline was accidentally leaked through a piece of thumbnail artwork on Nintendo of Korea's website shortly after the game's announcement, but was quickly removed. Her inclusion would later be confirmed in a dedicated Nintendo Direct aired on June 18, 2025, where it was revealed that she was Spoiler:the true identity of the character Odd Rock.

At one point, Nintendo approached Vicarious Visions about developing a new game in the Donkey Kong series for the Nintendo Switch, initially reported by fansite DK Vine and expanded upon by video game journalist Liam Robertson. The title was intended to be a 3D platformer with an emphasis on movement, with a major mechanic being the ability to grind on vines. According to Robertson, Vicarious Visions worked on the early stages of the project for only six months before it was cancelled in 2016, as their parent company Activision Blizzard shifted more focus towards the Call of Duty series. Reportedly, this was "the last straw" for Vicarious Visions founders Karthik and Guha Bala, who left the studio that year to form Velan Studios, a company that would later develop Mario Kart Live: Home Circuit for Nintendo, while Vicarious Visions would be folded into Activision Blizzard in 2021. That same year, rumors began to circulate that a new Donkey Kong game was being developed in-house by Nintendo EPD, who had previously developed Super Mario Odyssey, and would ultimately turn out to be true in 2025, when Donkey Kong Bananza was officially revealed for the Nintendo Switch 2.

According to Donkey Kong Country animator and character designer Kevin Bayliss in 2019, when Rare co-founder Tim Stamper and Nintendo tasked him to redesign Donkey Kong and "bring it up to date", he originally wanted DK's design to be "compact" similar to how NES characters were previously designed, and wanted the character to show up "nice and clearly." When designing DK's new facial features, he used the same design as the Battletoads' eyes, noting that gorillas "look like they got this big brow". He later expressed frustration in 2025 that this design choice always made DK look "annoyed", in defense of a new, contentious redesign of the character first introduced in the 2023 film The Super Mario Bros. Movie and later incorporated into Nintendo's games starting with Mario Kart World.

Many players assumed that the redesign was derived from his appearance in the film, resulting in complaints that it represented a sterilization of the character's public image. Closer to the release of Donkey Kong Bananza, the game's producer Kenta Motokura and the character's creator Shigeru Miyamoto explained their reasoning for the redesign. Motokura revealed that the design was first conceived for Donkey Kong Bananza before being applied to Mario Kart World and the film, and was made to account for the former game's 3D gameplay. He stated that they first accounted for how players would spend the majority of their time viewing DK from behind before snowballing into more substantial "creative adjustments," using his design from the original arcade game as a reference point; Motokura quipped that they "returned to where it had all started" while overhauling his design. According to Miyamoto, the redesign was intended to make DK more expressive, citing Donkey Kong Jungle Beat as the starting point to the new direction they took his design.

In Super Mario Odyssey and Donkey Kong Bananza, Pauline's dance moves mimic her sprite movements in the original Donkey Kong arcade game. Also, during the "Jump Up, Super Star!" song number in the former game, the 25m theme from Donkey Kong can be heard when she sings "Odyssey, ya see".