The GM (Game Master) posts a situation you, the players, are in. You then post your actions, exactly one action per turn. Once all players have made their actions, the GM posts again, with the results of the actions and the state of the world around you. After which you post actions again, ad infinitum.
The action results are defined by a six-sided die roll:
[1]: Epic Fail. Whatever you tried to achieve, you didn't, and you made it worse.
[2]: Fail. You didn't, or couldn't do what you tried to.
[3]: Meager success: You didn't fail, but you didn't succeed either. Like trying to sit on two chairs but ending up on one.
[4]: Success: You succeeded in your plight. All consequences are now your problem.
[5]: Epic Success: You succeed in the most positive way possible. The universe will bend to your will.
[6]: Overshot: You achieved what you tried to achieve, but you made it worse by doing so in the most inhumanely overpowerful way possible. Casualties are inevitable.
In addition, if at any time something threatens you, you get a free roll to dodge it. If you end up in a very bad situation as a result of the first dodge roll, you may or may not get another free roll to narrowly escape death.
Swarm rules: Each successive dodge roll during a turn, unless it is a dodge against the same object or character, will get a -1 bonus.
Status rules:
Status changes:
Dizzy: You cannot perform physical movement accurately, -1 physical actions. May cause vomiting.
Dazed: You cannot focus on your surroundings, -1 physical actions and dodge, -1 mental actions.
Stunned: You cannot make your body obey your orders, -2 physical actions and dodge.
Confused: You cannot get your thoughts into order, -1 mental actions.
Unconscious: You cannot move your body or react to surroundings, -2 to physical actions, no dodge, failguard.
Asleep: You cannot move your body and cannot discern reality from dreams. -2 to physical and mental actions, no dodge, failguard.
Trance: You are in an altered consciousness state and have trouble reacting to surroundings, -1 physical actions and dodge, no failguard. Deep trance gives -2 penalty.
Some status effects may grant "failguard". For the duration of these effects, the final total of any action roll will never be below 2.
If you are Stunned, Dazed, Dizzy, Confused, or otherwise receive a temporary penalty to overall or individual rolls, this penalty lasts until your next action is resolved, and not through the whole turn.
Sleep, Trance, and Unconsciousness are inflicted at a default severity that degrades with each attempt to overcome it.
If you receive a long-term effect that has the potential to alter itself, you get an Effect Resistance roll immediately after your action is resolved to determine the spread and consequences of the effect.
If you receive a mortal wound but are not killed outright, you need to pass a roll to avoid death at the end of every turn.
Combo rules:
You can spend your turn to help another player achieve his goal. If your roll is higher, it is taken as the success roll for the action.
You can also spend your turn to botch another player's action. If your roll is higher, its opposite is taken as the success roll for the action.
In both cases, individual player rolls determine what happens to the players in the course of the action.
Action rules:
Some actions may be considered "free", depending on the circumstance, and not require a roll.
As such, these actions can be paired with normal actions without penalty.
i.e. Pulling the pin from a grenade and throwing it is one action.
NPC rules:
When interacting with NPC's, a player can affect the action choice of the NPC via persuasion or hypnosis. In any case except direct physical control, the action of the NPC will be carried out in the NPC phase.
In extreme cases, regular players can be treated as NPC's. In these cases, the action will be carried out by the player in his own turn, and the effect that changes his action will be considered a positive Combo.
Any character that is not controlled by a player, be it because he is on AI, or insane, or mind-controlled by an NPC, or just about any other reason, will have a roll determine the general aim of his action for the turn. NPCs usually have an aim in mind, but insane NPCs follow this mechanic as well. The roll effects are relative to the players, specifically:
[1]: The character will do something VERY detrimental to the players. From going on a muderous rampage to destroying something the players need.
[2]: The character will do something detrimental to the players, and beneficial to him. Attempting to steal someone's item, killing a friendly NPC, pulling a lever that opens the exit and closes the treasure room with all the players, they all go here.
[3]: The character will do something for himself, without specifically aiming to do anything to anyone. Excercising, gaining skills, picking up equipment, just killing a horde of elves because they happen to be there, all fit here.
[4]: The character will do something that benefits him and the players both, usually helping in an action or just doing something the rest of the team is doing.
[5]: The character will do something beneficial to the players most. Finding a hidden button to stop some deathtrap, endangering himself to heal someone, etc.
[6]: The character will do something good for the team, but will be very excessive in his approach to the problem. Shooting a closed door with a rocket launcher to open it or summoning a nuke to destroy a nearby band of brigands will go here.
Enemies in this state will be less inclined to help the players even on high rolls.
Additional game rules:
Permadeath is in effect. This means no "ghost" characters, but the player can still get raised and isn't kicked out at once. On a bright side, if you didn't get in the first player roster, you can take a slot once someone dies permanently.