Zhazam is an app written in Swift using MVC architecture with 27000+(March 2, 2019) downloads. This app is created to increase user's typing speed in gaming form. There are 2 interesting modes, such as Classic and Timer. Also user can track his score. Insipired from www.typeracer.com.
Link: https://itunes.apple.com/kz/app/zhazam/id1424168976
Code is not so clean, because I wrote it at the beginning of my iOS path.