CATastrophe game mechanics

D6

"The basic mechanic of this system is to roll 1D6 and multiply the result by the attribute you are using in a particular situation.
Usually the GM decides on a target number, which the roll has to exceed in order to be successful, but in the case of opposed actions (where two characters are directly opposing each other), refer to the Combat rules, below.
If the group finds it appropriate, a player can decide which attribute gets used for his player’s action. Maneuvering in a situation in order to use your better attributes instead of the weaker ones is an important part of the game.

If your ability is at 0, you automatically fail the check.

4-6 Easy
6-8 Ordinary
8-10 Difficult
10+ Very Hard

Combat

In this game, “combat” is what happens whenever characters are opposing or competing with one another.
This covers the usual forms of RPG combat like sword fighting, magic, and firearms, but it also comes into play when players are in some way opposing someone.
The GM (or sometimes the players) should choose which attribute a player uses for combat, and this is used for an opposed roll.
Also, regardless of how many players and NPCs are participating in combat, their actions are basically simultaneous.

The Attack Power of an action is 1D6 times the relevant attribute.
Whoever’s action has the highest Attack Power wins that round of combat, while the opponent(s) (here, we are calling the loser the “defender”) are subject to physical harm in the form of Stress.
The opponent suffers Stress equal to the attacker’s Attack Power divided by the attribute the defender was using against the attacker, rounded down.
If the defender’s relevant attribute is 0, they take Stress Equal to the full Attack Power. If both combatants roll the same Attack Power, then it is a tie or stalemate and neither side takes any damage.
When several characters are working together, whether for attacking or defending, their respective Attack Powers are added together.

If a group acting together is taking Stress, one member of the group (PCs take priority over NPCs, players must choose one from among themselves and not simply dump the stress on to non-player characters) will take all of the Stress points.
When a players takes Stress, note it down next to her Spirit rating.
If a players accumulates more Stress than her Spirit, she will have a Stress Explosion.
If you really don’t want to have a Stress Explosion, you can opt to do whatever the opponent wants, and thereby not take any Stress.
Think about what you’re doing before you start walking down this path.