This app is a special edition of the Fierce Tales: The Dog's Heart game. By installing it on your Mac you gain access to the storyline and to challenges from the aforementioned puzzle game plus a strategy guide, a bonus chapter, the background music files, and the concept art and wallpapers.
The introductory cinematics shows a villager running for his life. Three possessed dogs are chasing him to a cliff where he ultimately finds his death. In my opinion, after seeing this animation, I wouldn't recommend this game to children as it's frightening to watch and play.
But for adult players Fierce Tales: The Dog's Heart Collector's Edition might seem the perfect way for spending their spare time. The puzzles are challenging and different from one another, with nicely-drawn background images.
Your objective is to find out who or what is causing the vicious attacks in your village. During your investigation you will collect clues, solve riddles, and interact with many interesting characters.
Another thing I like is that you can always check your notes or the strategy guide if you're not sure how to proceed with your investigation.
As a conclusion, I'd say it's worth buying Fierce Tales: The Dog's Heart Collector's Edition. The app is filled with many challenging puzzles, lets you choose between three difficulty levels, and automatically saves your gameplay progress.