I have this idea of a game kicking around my head. Given that and half a year of free time, this is a good time for actually trying to design a game.

The text that follows is likely long and hard to understand. So ask questions. This all is in development and up to change. Not everything is written here.

So, a game in which you get to totally alter a reality, or a few of them.

Here be setting material: There are infinite different worlds. Each of them different. They cover all possible worlds. "World" as in a universe, a megaverse, whatever. Amber is a world for this purpose, as is your house.
Occasionally some more-or-less random folk get tie to gether for some reason, in some manner. They start to alter reality around them in specific ways till they meet each other. At that point, something happens. Something big.
They are who the players shall play. Primarily. They can be people, cats, rocks, telepathic breams, whatever. Just make them interesting.

Basic structure of the game works thusly;
One player plays his (or her) character. The player counter-clockwise from him plays the setting and frames scenes. Other players introduce NPCs (kind of) and play them.
PCs can choose to shift the reality they are in, in a specific way. This moves them "closer" to each other. It also strengthens their power, so further shifts have more effect.
Endgame happens when everyone meets. This, by default, takes 5 shifts from each player. This is a dial easily switched.

From now on, "next player" and "previous player" have very important mechanical effects. Skip them not.
Chargen: Each player makes up a trait. This should be something the player knows a lot about (if it is a skill or such in the RW) or has a clear vision of (in case of alien stuff , such as magic).
In addition, each player selects the shift his character must live with. In theory, these know no limit.
Here are some suggestions: Elements (Greek, oriental), alignments, concrete objects, shapes, emotions
Everyone should be comfortable with the choices. I repeat: everyone should be comfortable with the choices.
The sitting order: Every player is seated between two other players. These places are fixed once determined. Everyone GMs for the player next to him.
Record traits: The trait you selected has value equal to the number of players present. Your char also has the trait selected by the next player at [number of players]-1. All traits are given value like this, so one ends up with his GM's trait at 1. This is a feature.

Example, because the explanation was not clear: Four players, Jim, Bob, Kat and Jack, sitting in that order. Jim GMs for Bob, who GMs for Kat, who GMs for Jack, who GMs for Bob. Jim has trait "War veteran". It has value 4. Jack has it at 3. Kat at 2. Bob at 1.
Hope that was comprehensible.
Shifts do not have values, nor do they affect each other.

Actual gameplay: For example, Jim starts. He frames a scene for Bob to be in. Then he simply bangs the Bob with stuff related to the traits in play, especially "war veteran". Other payers can, at will, introduce and play NPCs in the scenes framed.
The point is to convey what those traits mean. A war veteran is likely to know a bit about weapons. If the player in question doesn't know about weapons, too bad. That is why he has so few dice there.
The dice should be there when events are not clear. Any player can request them brought into play.
Resolution: Each participant rolls relevant trait. NPCs use d6, number equals 1, half the players, equal to players, or rarely something else. Up to the player controlling said NPC. Setting uses d10s, amount of which equal the NPC's. GM's ground. Player has dice equal to the trait value, size d4. This increases by 1 step per shift. It is d20 when the characters finally meet.
Successes are determined as they are in Sorcerer and Donjon. So, the dice that are higher than any of the opponent's are successes. Each success gives one fact to narrate (though multiple successes can be put into single fact). This fact is recorded (if it is likely to affect gameplay later) and it can be invoked to gain bonus dice, equal to the number of successes put in it.
In case of draw, a noninvolved player gets one fact. If everyone was involved, all those who were not the loser gain facts. If everyone draws and is involved, everyone gets one fact.
Characters can't stay dead. Killing one causes a shift, which either resurrects or stops death, as appropriate.
Details are up to the gaming group.

A player currently playing his own character can start a shift. This increases the importance of his particular shift. So, having vengeance as a shift and shifting means that vengeance becomes more prominent in the world.
First shift, which moves the palyer from d4 to d6, only has superficial effects. Like more movies on the subject matter. Every player, starting from the initiator, describes one such effect. This goes until the initiator frames a scene for the next PC. Some minor effects of the previous shift should be present.
Increasing the die type to d8 causes a limited minor effect, like somewhat increased numbers of violent crimes amongthose who enjoy movies.
To d10: Minor effect, but affects everyone.
To d12: Major effect (like bloodfeuds becoming legal and accepted)
To d20: Cataclysmic effect (men and beasts alike pay every slight tenfold)

And anyone who doesn't know what incoherent and personal notes look like can read a sample here.