The Gist:
A group of random individuals awake to find themselves naked and sprawled on a strangle circle much akin to a spell circle with runes with nothing more than themselves. These individuals will find themselves in a world similar to earth, except that the air is cleaner, there are no human built constructs of any kind in sight. No roads, no skyscrapers, not even the sky trails of planes.
These individuals will find themselves clustered and must work together to survive.
They must secure food and water, they will find fruits and seeds similar to those of earth, but they will also find those with completely difference visages. Everything will be a risk, from the fish they find to the crystalline water they drink.
Due to the fact that some events can kill or incapacitate your character multiple character creation is not frowned upon as long as you are aware that the more characters you create the more likely that one or more will die for the sake of simplicity. Keeping track of too many people will burden and strain the story.
It will be fantasy, the world will have many fantasy elements including monsters and objects with fantastic effects. All of these will be discovered on the go.
Also I believe that a great story is made by chaos, meaning that while there is a certain way things should flow, stepping out of bounds and doing your own thing is not frowned upon as long as there is a reason for it. You decide to assassinate someone just because you felt like it is not a good reason, say you want to off him out of spite for an action he committed against you or out of jealousy because a certain other individual pays more attention to that character ran than yours...well then you got yourself a reason.
This will be a test of quality for the RPers as well, outside the box thinking and coping with events that do not flow in your favor.
I also do not shy away from extreme actions and behaviours as long as you keep it implied when XXX is involved.