Board Thread:Questions and Answers/@comment-188.2.16.196-20161129213621/@comment-107.130.170.163-20161202185456

It's possible to complete it if you constantly buy sticker packs until you get them all. Not saying it's a tempting option or even a fair one, but it's the one the creators are going to stand by. I think replacing the one useless power-up in the cards with stickers would be great, but I doubt it'll ever happen. And as the person above me said, guessing the killer isn't something that would ever be implemented for a variety of reasons. It seems we'll just have to deal with getting the stickers we do get and if we truly want more, buying more.