OS: iOS
Price: Free (used to be paid)
Developer: Dennis Rava
Type: Games
Monetization: ads

Simple, simple, simple. Turning the tiles to match the example. Nice UX. Nice colors - not great but nice enough.
A good example of an app that can be built relatively fast.

As for Monetization - the app can do much better that the admob banner running at the bottom. I would recommend trying interstitials and/or appwalls, for a start.