Once they'd ironed out the technical difficulties, the team had to work out when stereoscopic 3D worked best, to make the most innovative levels. "It looks really good when going down stairs," said Hayashida, "which led us to world 1 - 3 [a series of cloudy plummets]." Similarly, it looks very good in small square rooms with high walls, which led the team to create world 5 - 2, which they call 'the Zelda dungeon': "If you get to this stage, get on this block in the middle and jump, Mario will pop right out of the stage."
To embrace the hardware, Miyamoto himself challenged the teamto take another approach to stereoscopic 3D - optical illusions. No one on the team had ever tried to make one before, let alone in a game, so Hayashida himself took on the task of making an illusion that was resolved when the 3D slider was on. He ended up using this to create many of the MC Escher-style staircases hidden down the game's multiple warp pipes.
With all these new concepts, the team had to consider how difficult they were making the game, which led them to the P-wing level-skip device. "The developer isn't the one who decides what is fun in a game," said Hayashida. "If someone wants to skip a hard stage and go straight to Bowser, they should be able to. Our challenge is to get players to come back and complete the levels they skipped." For this reason, the game's ending is earlier in the level structure than normal, allowing better players tobeat the game easily, but also encouraging them to explore the advanced levels further.
To make sure the game was still accessible, Hayashida tested it on his six-year-old son. Clever design won out again: "He got game over after 30 minutes. He spent an hour clearing the first level. But he told me: 'Collecting coins is fun, dad!' I understood that while he missed the intended objective of the game, he still enjoyed it."
Later, Capcom's Kawata addressed Inafune's challenge about Japanese game development more directly. "The social games market is doing well, so as a business the games industry is fine," said Kawata. "We should be researching what the world wants. Ithink the stuff that sells overseas has hit a level of quality that matches the stuff that sells in Japan - but there are differences in cultures that need to be taken into account."