As far as I understand, iTunes search is now working on a keyword search as oppose to name search. Popularity of an app takes account to the search result. This may include app title, keyword and non observable values such as the download count, reviews, rating. They are then compared with other apps and rank them accordingly.
The Falling can be easily outcompete by "Falling Balls" (248,184 ratings) which currently rank #1 in the search result. You can imagine that how many downloads do they have. These versus 14 ratings on your app. You can imagine why Apple may view that the other apps are more relevant to the user.
Well then the word candy I entered should have clearly triggered enough parameters to return Candy Crush Saga as the 1st result. The search engine should be able to omit typos as well when they lead to negligible or irrelevant data.