So for the early missions the various quest shops are all in it together, us humans against the zombies. But perhaps as you advance in the quest arc, you are forced to choose sides-- advance too far in some arcs and you can no longer get quests from certain other shops. You might even eventually get banned from entering certain buildings.
* Rivalry between militia and army, and if you get too friendly with one, the other one kicks you out.
* The cult are actually working with the zombies and you have to either destroy them for one of the other factions thus preventing yourself from getting any more quests from them, or keep helping them and the other factions kick you out.
* Mercy Hospital is working on an anti-zombie serum, but one of the other groups thinks they are "playing god" and must be stopped.
* The army at the university decide that nuking downtown is the only way to get the epidemic under control, and they want you to plant the nuke. Some other quest shop located at the site of the nuke wants you to turn against the army and nuke the university instead. Whichever you nuke, all the interesting locations and quest shops within a radius of 5-10 blocks become destroyed and permanently inaccessible to you.

A little harsh, don't you think? A nuke is kinda overboard...and where do they get the nuke from, anyways? That I can't vouch for, but I kinda like the other ideas. I would, however, like to see similar quests from opposing factions, so you don't miss out on too much. And it would be cool to be able to choose a automatic shop's weapons over a rifle shop's goods by sabotaging one or the other to gain access to their weapons at a discount, or new "uber" guns available for sale.
P.S. Who in their right mind would want to work with the cult? All the things you miss out on, and what do you get out of it?

Interesting. You may as well throw in raider gangs as well as other organized crimes as part of the rivalries

Sounds interesting and realistic. I like the idea *thumbs up*

IF you want rivalries I think the cult isn'tactually trying to play "god" they are just slowly being degraded mentally meaning you would need to help them by getting certain factions.

...What's with everyone and the same avatar?

And I like the suggestion, Play everyone against each other, then benefit from their rivalry.

Default avatar now :0

That's why all myth members are required to have avatars

Kinda gettin off topic

Nashkir you will see plenty of topics derailed by the hands of myth members in your lifetime here on the forums

Yes I do although question remains should we have Factions?

Factions will eventually be implemented, I believe Rouge Military units, and Raiders we will be able to interact with are coming. (correct me if I'm wrong Admins)

Does that mean when we go to an area with someone who we have a bad faction with (Say the Cult) They will start attacking me?

I can imagine the usuage of an Affiliation meter if this becomes the case; complete too many selfish missions for Rogues and Raiders and you lose the confidence of the Military and supposed 'good guys' as your fame spreads, but work for them too much and the raiders cannot trust you either and will attack you more often. This means keeping your Affilation meter roughly in the middle will allow you to do missions from both sides but not the really big ones!!

There should be ways of easily doing things to knock the meter either way; raiding cop cars and army vehicles will knock you towards the favour of the raiders while killing raiders will put you in favour of the Army, and then of course you still have all the neuterals around anyway...

Since this thread got already necroed, I must say I like McDave's idea.
Of course there would have to be only a slight difference between the two sides, to keep things balanced and simple, but if implemented carefully, it might be pretty awesome.

With the exception of that "raiding cop cars and army vehicles" part.
If by "raiding" you mean "looting", than it's a no go, because military and police vehicles tend to have pretty good drop rate for ammo, weapons and other usefull stuff

Yep. Makes being a bad guy all the more tempting... Lol