The main objective of this game is to reach the end by solving every level.

A typical level will have the main area where you can see some images, a left floating button that opens the input area, a centered floating button where you can have access to some hints and a right floating button that opens the log.
The input area is where you place the answer(s) to the riddle in question.
You can watch an ad and be given a hint, specific to the level in question. Different levels have different amounts of hints.
The log contains clues or relevant information that you need to analyze or decode and determine whether it is of use and its relation with the main area, which also contains clues.

The password located in the app bar 'Level Y - XXXXXXXX' is used to teleport directly to a level without having to start over. This means that you will have to take note of the passwords as you go through the levels, so you can return to the latest one.
Passwords are generated at the time of the app installation. This means that if you decide to uninstall the app and later come back to it, passwords won't be the same. It also means passwords won't be the same in different devices, so sharing them won't work.

Warning:
The game is hard. It involves research, assumption making and sometimes maybe a little guessing. You may immediatly recognize what is going on in a level or you may not know anything at all. It may be an easy, direct level or it may be a complex, step-based level.
It is not supposed to be a fast game, but something that takes time. Brainstorming with a group of friends helps.
Hints help a lot too, so if you want the challenge, either don't view them or only get the first few.
Take this into consideration when deciding to install.