I have the basic concept of the game, so far. I was thinking about epidemia like game.

For now, there are only some basic ideas:

• the virus spreading all the world, 
• there is no possibility to save all of the population,
• it is time of hard decisions to take, (this is where "The Lesser of Two Evils" theme is met)
  
• there is certain amount of time for population to survive - more survivors scores better, but if no one survive game is over
• there will be 3 (maybe more) episodes (waves) with short plot each,

Game mechanic concepts:

• 2d map game,
• map is divided in world regions (fields),
• each region has own population, 
• virus spread on adjancent fields, on every game step, and make new regions infected,
• people are in panic mode, and travelled as far away from the infected regions as they can, on every game step,
• player can place certain amount of quarantine zones on regions, which attract people to travel to,
• player can also drop nuke bombs on certain regions, which kill all viruses on that region, unfortunatelly people too,

I am trying to manage some time among the real life challenges ;). 

So, I hope game will be on time :)