When Takashi Tezuka served as assistant director on the very first Super Mario Bros. for the NES, creating levels was a laborious, time-consuming process. First, a designer would sketch out their vision for a level on graph paper. Then they would bring the drawing to a programmer, who would try to translate it into the actual game. This process would happen multiple times, as the team adjusted each stage to get them just right. “That cycle really took a long time,” Tezuka explains.

It’s a far cry from his most recent project where Tezuka served as producer on Super Mario Maker 2 for the Nintendo Switch, which launches today. Like its predecessor, it’s more of a tool than a game, an intuitive and playful way for players to craft their own 2D Super Mario levels and share them with others online. Players can create obstacles and then test them out in seconds, and it’s all done via the Switch’s touchscreen. It’s the kind of tool that Tezuka would’ve killed for when he was designing games in the early 1980s.

“I’m always thinking about that,” he says with a laugh.

Despite its current status as the Switch’s big summer release, Super Mario Maker didn’t actually start life as a commercial product. Instead, it began as an experimental prototype within Nintendo’s tools team, who were trying to make it easier and faster for designers to put together 2D Mario levels. As soon as he saw the prototype, Tezuka — who started at Nintendo in 1984, and has worked on nearly every Super Mario game, serving as director on everything from Super Mario World on the SNES to the mobile Super Mario Run — realized that it could be something much bigger. Not only was the tool intuitive, it was also a blast to play. (When asked if that internal tool still exists for making Nintendo games, Tezuka says “it’s actually a secret.”)

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The first Super Mario Maker launched on the Wii U in 2015, and it almost immediately spawned a dedicated audience of would-be level designers. Users created everything from punishing death traps to inventive levels that used goombas and piranha plants to tell a story. Tezuka distinctly remembers seeing someone make a working calculator in the game, and he was always impressed by the automated levels, Rube Goldberg-style contraptions that pushed players along without any input. “We knew that those types of courses were possible,” he says, “but seeing the specific shapes they took, and the lengths that people went to to make them, it really took us by surprise.”

For the sequel, there were a number of elements that didn’t make it into the first game that the team wanted to revisit on the Switch. One was online multiplayer play, and another was a more robust story mode that offers more than 100 pre-built levels to play from. There are, of course, new building blocks for budding designers, and Nintendo also added a very detailed series of lessons on game design, covering everything from specific mechanics to philosophies on game difficulty. It’s so in-depth, in fact, that Tezuka occasionally wondered if it was okay to give away so much of the company’s “course-making secret recipe.”

For the sequel, the team also had the advantage of being able to observe the community from the original game, and use that data to shape the changes for Super Mario Maker 2. “As developers, we are always keeping an eye on what people are doing and the courses they’re making,” Tezuka says. “We take that in and it inevitably becomes a part of what goes into the game’s development. I think it’s probably safe to say that the biggest way it influences us is just being reminded of the fun of creation.” Without getting into specifics, Tezuka says that many of the changes for the sequel involve quality-of-life updates, in particular ensuring “that the environment we’ve created for people to create courses and play courses in is one they feel comfortable in, one they feel safe in.”

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There have been more than 20 mainline Super Mario titles released over the years, and Tezuka believes that the enduring appeal of 2D Mario games comes down to their accessibility. “They’re immediately easy to understand,” he explains. “They’re simple: you see it and you know what you need to do, you know where you need to go. And so many, many people are able to understand and play those games right away.”

Meanwhile, for Tezuka himself, who has spent decades with Nintendo’s block-hopping plumber, you might think he would get bored working on the same series for long. But he says that he’s constantly inspired by advances in hardware: whenever he learns about the next Nintendo platform in development, it always gives him new game ideas. That could be anything from the advent of 3D graphics that led to Super Mario 64, or the touchscreen-centric controls that shaped Super Mario Run.

“I really enjoy that kind of challenge each time,” he says.