I think that you use specific amiibo to collect amiibo tokens which are then used to unlock levels in the Star World. I've just completed all the stages that you can play with any amiibo and I really enjoyed it. Anyone who liked Tipping Stars, or wants to try it out and has an amiibo, should definitely download it as soon as possible.
The gameplay is just like Tipping Stars, which I loved, but it adds a new layer with amiibo abilities. You can even switch characters within a level, as sometimes you need multiple abilities to grab everything, which adds more challenge to the game, if you're looking for it. The great thing about this, like Mario vs. Donkey Kong: Tipping Stars, is that you can tailor the difficulty to suit what you want. You can collect every single coin and amiibo token, while also using a character specific exit, in one run and as quickly as possible if you really want to test your skills. On the other hand, you can take your time and just collect as much, or a little, as you like and even replay the level to grab each token on a different run. The choice is yours!
There are 13 levels available when you scan any amiibo which I managed to complete in under an hour. I went for all the coins as well so there doesn't seem to be much to do but it's a great bonus for anyone who already has an amiibo, especially as the gameplay is fantastic. If you enjoy it, I heartily recommend Tipping Stars. In fact, I suggest that you buy Tipping Stars anyway, if you like puzzle games. I think that each amiibo unlocks 4 extra levels but only the ones below have their own new levels to play. You then have 9 more Star World levels to unlock by using amiibo abilities to collect amiibo tokens which unlock those Star World levels.
These seem to be the amiibo with special abilities:
If you don't scan one of those amiibo, you'll play as Mini Spek who doesn't have any special moves. I played as him (it?) because I wanted to see how much I could do with any random amiibo and Ganondorf was the closest one to me
. It's a shame that other amiibo don't at least have their own models, as I was hoping that it would be Shulk time. I have all of the amiibo in the image above, except Luigi and Peach, so I'll be replaying it to unlock as much as possible.
Ultimately, this is a great bonus for anyone who owns an amiibo and you should definitely try it out, if you have an amiibo. You can't do anything without scanning an amiibo but, if you like the look of the gameplay, Mario vs. Donkey Kong: Tipping Stars is very similar and it comes highly recommended from me so be sure to check that out, if you haven't done so already.