Esoterica: Hollow Earth 

Esoterica: Hollow Earth is a puzzle game developed by Alawar that tells the story of young Stephanie, a scientist who adventures to the depths of the planet. Your goal is to go on the footsteps of your grandfather and initiate a machine that helps you get to the center of the Earth.

On your journey you will need to collect various useful items, solve challenging riddles, and complete hidden object mini-games. At your destination there's a mysterious continent called Agartha.

You can always use hints if you're unsure about your next move, check your goals list, and skip challenges if necessary. Another good thing is that you don't need to save your progress every time you complete a mini-game; the app does it for you.

One thing I didn't like was that the text content is very difficult to read when playing in windowed mode.

Another small disadvantage is that the cinematics don't look as impressive as expected. Taking into consideration that the scenes and mini-game screens looked pretty impressive, some work on the cinematics wouldn't have hurt. For instance, when it plays a dialogue between two persons, their faces don't move at all. Their accents sound a bit odd (a combination between Dutch, French, and English).

As for the rest, I enjoyed playing Esoterica: Hollow Earth. The app brings a fascinating plot, provides you with various types of puzzles, and comes with an affordable price.