TomaTito on 21 August 2015
Apparently there was more footage in the Cat Mario Show: https://youtu.be/1JLXeEtmK_I?t=421
And the amiibo functionality has been discussed in Amazon Japan's page. It states that Mario, Luigi, Peach, Toad, Yoshi, Bowser, Link, Kirby, Meta Knight, and King Dedede work with Picross 3D 2. By using any of these amiibo into the game, players can unlock original puzzles.
This is what the Mario puzzle looks like.
Sounds better than the amiibo Splatoon locked content.
