How Mario Kart influenced Nintendo's fighting game, ARMS

“Though they are different genres, Mario Kart and ARMS are like siblings,” said Kosuke Yabuki, Game Director of Mario Kart 7 and 8 and producer of ARMS at the 2018 Game Developers Conference.

While there may appear to be few surface-level similarities between the games, Yabuki argued that lessons learned on Nintendo’s long-running racing game series informed many aspects of Nintendo's new fighting game IP.

It was while chatting with a designer on his team, that Yabuki began to consider the possibility of creating a fighting game where the camera was position behind the player’s character, as in Mario Kart, rather than from the side.

Fighting games typically use a side-on perspective because it makes it much easier for the player to judge the distance between combatants, he said.

What if it was possible to position the camera in such a way that players could have the same sense of spacing and control from a Mario Kart-esque behind-the-character perspective?

Yabuki’s team prototyped the idea using rudimentary 3D characters whose arms extended across a boxing ring, to give a clear sense of distance and space. As in the final game, players could switch apply different weapon-like fists to their characters’ hands, and bend the arm as it extended in order to chase its target.

“It felt like a shooter in a way,” said Yabuki. “Even at this early stage, you could have a tactical battle.”

“Very few of the prototypes that the R&D teams design at Nintendo blossom into commercial games,” Yabuki said. This is because Nintendo expressly looks for game ideas that deviate from existing game styles and fashions.

“If [Shigeru] Miyamoto asks me the question: “What’s different about this, and I don’t have an answer, then I’m finished,” he joked.

As Yabuki's team added art and animation to the game, at first only the fist extended. They found that the action on screen was too slight and unsatisfying. When the team changed the animation so that the entire arm extended, ARMS found its essential and defining novelty. “Flicking the Joy-Con made it feel like your own arm was extending into the screen,” Yabuki said.

Extending arms also felt like a Nintendo-esque conceit. The team did not feel that the extendable arm function needed to be explained in the game’s fiction. “The answer to the answer to the question: ‘Why do these characters have extendable arms?’ is,” Yabuki joked, “Because Nintendo.”  

“Using a behind-the-back camera allowed us to flesh out the 3D stages, something we’d been doing all along for Mario Kart,” he explained. The team put “a lot of effort and thought” into the characters’ clothing in order to get across that this is a serious sport in the ARMS world. “When working on Mario Kart 8 we made a lot of fictitious brand names and logos, and we were able to use that experience in ARMS.”

ARMS also drew inspiration from Mario Kart in the way in which it introduced the element of luck into the competitive arena. “The luck element in Mario Kart is huge,” Yabuki said, in reference to the race-upsetting role that shells and other items present in the racing game series.

“That element of luck is also present in ARMS”, specifically in the sense that players don’t know precisely where the punch will go, or whether it will land dependent on the opponent’s actions.

With such a variety of different character and arm permutations in the game, Nintendo used AI matches to ensure that no one particular combination was significantly better or worse than another. Balance has continued to be tweaked post-launch, he said.

“We also spent a lot of time considering the characters’ athletic bodies,” he said. “That is, admittedly, a little different to Mario Kart.”

In pursuing the art and technique of good game design, no experience is wasted, said Yabuki. “Good game design is universal.”