I will describe below a mechanic. I have not implement it yet, so I can still change things. I'm looking for a simple what you think about it (if I should implement it or not or change something, maybe something should be adjusted, etc), even simple "pathetic", "I won't play it", "I love the concept" would be helpful.

Older topics (similar):

http://www.gamedev.net/topic/660026-emperor-and-rebels/

http://www.gamedev.net/topic/670355-loyalty-etc/

Mechanic

You are the Emperor of a space empire. Important part of the game is an internal struggle (so not only fighting aliens), major part of it is rebels mechanic.

There is an abstract "rebel power" which accumulates over time (because people are unhappy, due to food riots, a secret organization wants to overthrow you, imperial officials being disloyal, alien plot to destabilize the empire, etc), it's basically a sum of various factors. When the rebel power reaches a certain thereshold a rebellion event starts (and the rebel power variable resets). There is no distinction who the rebels are, it's a generic rebel forces (entities that are unhappy with you being on the throne) that want to conquer the imperial homeworld.

So, rebellion, once it starts, is a sort of game mode. Until it ends the rebels will spawn forces, attack imperial planets, take over planets politically, etc. If you are unable to crush the rebels (make so there are no rebel controlled planets anywhere in the galaxy) within 50 turns you start losing prestige and eventually will trigger a failure condition (so you can't go for status quo, you have to crush them or lose the throne). Also if at any time the rebels control the imperial homeworld you instantly lose the game.

Details: At the start of the rebellion event 3-5 planets turn rebel (probably the outskirts ones, homeworld and near homeworld planets are immune). Then rebels start spawning rebel forces (each turn, but much more at the first 5-7 turns of the rebellion). Eventually they stop spawning new units (turn 10-20) except for small contingent allowance per controlled planet (sort of production, rebels in fact do not produce anything). They will have an option to politically take over a planet (without a combat and only if the planet loyalty is sufficiently low and is neighbouring another rebel planet), but only during the first 12 turns of the rebellion. Then they fight with you over the control of the planets. If you crush them within 50 turns you are fine, if not you start to get penalties and eventually lose the game (like turn 70-80 of the rebellion). There is no negotiation with rebels :)

Additonal mechanics/questions:

- I wonder about just one variable "rebel power", maybe make it more complex? (but reasonably, I don't want to/have time to make a rebellion simulator :D)

Why rebels have to attack empire even though they secured several planets and it is almost certain that they will lose? Rebels could just be other faction like aliens, you could even look for a peaceful transition back from rebel planets to Empire.

And it can also be like Tropico riots where rioters demand something and if you accept they disperse (not always though).

Rebels can easily work in a number of different ways, depending on how you want your game to run and the number of layers you wish to work with.

The most obvious being that a number of planets switch from your control to the rebels, and then they act as an enemy force. Depending on the 'type' of rebel, they can sit tight and just secure their own borders, raid nearby imperial worlds/fleets/supply lines, or attempt aggressive expansion.

You may also want to go with a deeper layer, where rebellion becomes influenced by 'agents' who go to a planet and stir up trouble. Support for rebellion then raises if you fail to address the agents and issues they are acting on, such as food shortages, cultural issues, labour issues, etc.

You could also have factions who might use terrorist style attacks to drive their own agenda by attacking planets belonging to other factions within the empire, and if you don't do anything to address the aggressive faction then the other factions being affected by the aggressors will splinter off and deal with things themselves.

The big thing is to keep rebellion from simply being 'whack-a-mole'. If the empire is made up of various factions and agencies who interact with each other, then give the player tools to help balance various groups against one and other. You don't have to send in a war fleet to suppress a rebellion, but maybe you could instead support a trade federation and supply them with ships and weapons, and give them a mandate to deal with a sector. Of course, that could come back to bite you in the ass 50 turns later when they decide that they have the force power to oppose you and take a chunk of planets for themselves instead.