all of those are good examples but i still think the primary tension in this game will be from the choices and long term survival. sure there will be events that happen in combat or otherwise that will cause it but the tactical decision making will be a calculated one rather than an "oh crap" what do i do now response.
Long term and survival exclude themselves.
Survival is a struggle against a short term unit. As soon as you are able to think long term, you no longer struggle for survival.
You have a back pack. The back pack contains enough food and water for four days. That is the short term unit: you have four days to find ways to fill up the back pack.
As soon as you accumulate like ten times the content of the backpack, logics of survival is changed in something.
This game can be an oddity if the developpers go for a survival game because they will have to go against a player common demand: usually, most players do not want to survive in a game universe, they want to dominate it.
They want to start small and later grow in the dominant force, they want to be beyond survival in the middle-later stages, through hoarding various resources, money, weapons, character's skills etc
I wonder if the developper will go for a lost cause approach, when your best gain is living one day more or a king of the hill approach and answer to the player's expectation of power, allowing to grow into a powerhouse in a world filled with zombies.
Another question is whether you will be able to think long term "survival" through multiple playthroughs. You know the ropes. Will the game allow to project oneself up enough to remove survival and will the means of survival be uncertain enough that through knowledge of the game, you can not be sure that when chosing this or that, you will get what you want?
Will the game universe renew itself enough that you will be given no guarantee when selecting a means of killing zombies, a new member of the group etc or will you be able to think the game globally, with patterns like "okay, I know that this means will not be that useful at this stage of the game, but it will pay off big time in the later stages"?
Very curious to see the end product. A funding means like kickstarter should give the developpers the liberty to developp a survival game as it is prepaid.
Survival is not about being powerful. It is about being vulnerable, with a limited horizon on the future. Players enjoy playing games for power, for growing more and more powerful so here, a tension exists.
If the player and the group can grow powerful then it wont be about survival.