The Legend of Zelda: Tears of the Kingdom

Fujibayashi pitched Ultrahand with a playable demo built in the existing engine. Director Hidemaro Fujibayashi used the Breath of the Wild engine and its spinning dungeon cogs: four cogs on a stone slab made a makeshift car, and four slates around a bomb and a ball made a cannon, together a DIY tank. Zelda bosses Aonuma and Miyamoto approved the proposal quickly.

Nintendo designers are encouraged to build prototypes before pitching. YouTube videos of players already building vehicles with Breath of the Wild's limited tools gave Nintendo extra confidence. The idea began as Link building his own contraptions, 'like a pointy-eared MacGyver'.

Remove complexity early so there is more room for freedom later. Simplicity was Nintendo's first goal: Ultrahand should feel like Lego or Minecraft, not like learning Blender. A fiddly tool overwhelms new players and frustrates those who only want to dabble.

Fujibayashi: "The more we weed out complexity upfront, the more versatility and freedom there is to provide options [later]."

Nintendo reworked building until a five-step raft became one or two actions. A basic raft first took five steps; the designers kept rethinking each part of the process until players could make a boat in one or two actions.

Coarse 45 degree rotation and snap points traded precision for speed. Ultrahand first rotated objects in one degree increments for fine tuning; the final game turns in chunky 45 degree steps, and objects snap together at set points so wheels and steering are quick to place.

Dozens of Zonai device ideas were cut to a bare minimum. Nintendo generated many device ideas such as fans, wheels, cannons and floating platforms, then trimmed the set to avoid decision paralysis.

Players still build impressive machines from the few devices that remain.

One weapon hit powers every connected device, replacing a separate switch. A separate switch item was tested and dropped; instead, striking any part of a contraption turns on all its Zonai devices.

A side effect is that players can start machines from a distance.

Building in the world with wobbly physics makes players experiment. There is no separate build menu: objects topple and crash as you move them, and wiggling the stick or Joy-Con breaks a creation apart.

"If you enjoy using something, it's always easier to experiment and learn."

Zonai devices copy everyday objects so their use is obvious. Devices resemble a desk fan, a skateboard, a fire hydrant and a light bulb, and the stabiliser copies self-righting toys like Daruma dolls and Weebles.

Aonuma: "if it looks similar to an everyday item, they'll understand how it should be used intuitively."

Batteries, gashapon machines and rope make the fiction readable. Machines run on big batteries instead of vague magic, gashapon dispensers signal a random selection of tools, and immovable objects are tied down with rope or cloth.

The visible glue stayed because it shows what is attached. Aonuma, a wood carver who hides joins, first found the glue seeping between parts ugly, then saw it as an obvious clue that two objects are connected.

Testers sharing videos of their builds signalled the mechanic would hit. Staff excitedly shared videos of their creations during playtesting, and Fujibayashi knew from that the mechanic would be a hit.

Some player creations still surprise Nintendo itself.

Funny failures are acceptable, so the physics can stay loose. A machine running away when accidentally activated or a wooden tank catching fire is fine "as long as players find those failures funny."

Recurring side quests like transporting Koroks and fixing Addison's lop-sided signs lean on the same slapstick and wobbly physics.

Open problems with many answers replaced single-solution Zelda puzzles. Instead of one intended solution, Tears gives tools and lets players choose, such as flying a custom goblin glider to a summit in seconds instead of climbing.

Dohta: the aim is to let players "do exactly what they think they can do, rather than how we want them to play the game." Aonuma saw players taking pride in their accomplishments and finding their own playstyle. Nintendo gave up designer control over how puzzles are solved.

Cheeky cheats are welcomed because they feel like a personal discovery. Many obstacles can be beaten in unanticipated ways with Ultrahand, Fuse, Recall and Ascend, and a clumsy cheat is fun because the player feels like the only one who found it.

Nintendo nerfed perpetual motion machines but kept room for creativity. Testers quickly built perpetual motion machines that crossed the map on infinite power, and these had to be nerfed for the game to work.

Fujibayashi's team spent years finding limits that allowed creativity while the game still functioned as a game, through endless iteration that kept the tool from being a buggy mess.