According to Cain

I helped beta test this game.

The idea of this game is that you are part of an alchemical society that possesses the ability to travel back in time. It is your job to go to the very beginning and discover the truth about Cain and his Mark.

The alchemical system in this game is rich. It consists of the four humours (blood, phlegm, etc.), their 'poisons' (substances that counteract them), and a host of other substances. It is accompanied by a gargantuan book with many pages, dozens of them. It's too big to just read straight through, so I strongly recommend NOT taking the book as soon as you get it and looking up every topic you see; the game will guide you in using the book later on.

The main gameplay is unlocking memories of Adam, Eve, Cain and Abel through alchemical means, gathering more ingredients, and learning the mystery of this early world. Often you will told a formula you need, but for which you lack an ingredient or two and must find them.

There are some tricky puzzles I struggled with as a tester, including mechanical puzzles and flashes of intuition.

The game has a darker tone to it; this is an unhappy and grim retelling of Cain and Abel's already grim story. It doesn't conform to my personal beliefs, but it's clear this is a work of fiction and a well-written one at that.