GBB is a minimalist task resolution system designed around two concepts. These concepts are task and object. Tasks are attempted by objects. Both tasks and objects are free form. This allows total freedom to create any style, mood and universe wanted. With no rules or restrictions in the way, it's easy to make the game the way you want it to be.
Any single attempted function that can either succeed or fail is a task. These include traditional RPG elements like attacks and skill checks, but also much more. Tasks can vary in complexity, detail and duration as much as needed in any given situation. An object can be any functioning whole in the game universe. This includes traditional RPG elements like characters, but also, for example, machines, structures, equipment, spirits, ideas, foods, gods and countries can be objects. Five people can be one object, one person can be many objects.
One player should always be the GM, be the ultimate judge, just to avoid arguments. A simple way to define objects is to write a bunch of one sentence long descriptions. Any method can be used. Tasks should be defined as a collaboration between the players and the GM. Dice can be used as much or as little as you want. One sentence long descriptions are a good way to record damage. Amount of damage should follow directly from the definition of the task.
All you need is the task resolution mechanic, the rest of this stuff is just to convince you that this one rule is enough:
Roll 2d6 and add modifier. If the result is eight or more it's a success. If the result is seven or less it's a failure.
The modifier is a number added to the result of the 2d6 roll. It can range from -3 to +3. Think of +1, +2 and +3 as good, better and best chances. An unmodified roll can be considered challenging. When deciding the modifier to use, concider as many aspects of the object and the surroundigs as you want to. You decide the level of realism and detail that best suits your themes and style. The margin of success or failure can be used to determine severeness of results if such detail is needed.
To add critical success and critical failure to GBB, concider all natural results of 2 (both dice show 1) to be critical failures and all results of natural 12 (both dice show 6) to be critical successes. These critical results are more radical and unpredictable than normal successes and failures. This critical rule can be used with or without the karma rule.
To grant players more control over the faiths of the objects they control, you can give them one karma point whenever they roll a natural 2 or a natural 12. Karma points are tied to the object, not the player. Karma points can be used as additional +1 modifiers on any task attempted by the object. When objects "die" their karma points are lost. If an object breaks down to smaller objects, the GM can decide which objects get the karma points. The points can also be lost. If an object is merged into a larger object, again, the GM decides. This karma rule can be used with or without the critical rule.