Poochy & Yoshi's Woolly World is a port of the Wii U platformer, Yoshi's Woolly World, for the Nintendo 3DS. In addition to all the levels of the original, this includes a new set of levels and new Poochy amiibo support.
Aside from graphical changes (there's less detail like the ground depressing around Yoshi walking), there is a set of new levels and new Poochy-related mechanics. Players can get mini-Poochys to help players find secrets in the level. They will hop onto invisible clouds and areas of the level that can be moved into to get a secrets.
New amiibo support
The main new amiibo support is in the Poochy amiibo