The first thing is, Mythus is not a game. Far as I can see not a single so called RPG qualifies as a game. The RPGs I've seen are complex, complicated, and essentially unlimited. A game is more properly limited, constrained if you like. A limited field of play, limited actions, limited goals. In something like Mythus the possibilities are not constrained, but rather nearly unlimited.
The term I prefer for such as Mythus is "Adventure Guide" (AG). A guide to adventure, and more particularly to adventuring in an imaginary world. A guide to playing the role of a person living in an imaginary world, and a person who tends to find himself in the sort of situations that could put your life in dire peril. Or which are just damned inconvenient.
Just as important, "RPGs" can not be about story telling. They do have elements of story, but given that you cannot reliably predict how an adventure will turn out they can't involve story. Just too unpredictable. "Story" is about predestination, RPGs are about free will.
In short Mythus is a guide to adventure, an Adventure Guide (AG). A guide to playing a role in an imaginary world, a fantasy world where goblins dance in seedy dives, elves lecture on metaphysics at the local college, and rakshasas give financial advice. Mythus is about life, and life can be adventurous. That's how I approach things and how I will handle matter in my upcoming wiki.
And please note that AGs don't have rules, they have mechanics. They have an engine or system consisting of the mechanics that describe how the AG works. Rules are prescriptive, mechanics are descriptive. Mechanics tell you how things work, and you can't cheat in all reality. (Yes, I have tried flying by jumping out off a window while wearing a cape. I was 8 and it was fun.)
So forget about all that crap about game and story and just have a good adventure. And remember that adventures aren't always voluntary and sometimes they come to you.