you should be able to turn in crystals to different rewards like money,skill points or maybe even a crystal of the next tier(for example 5 blue can be turned in to 1 red)
there should be more building types, like toolshops(building and expanding take #less days for each man) and gunshops(survivors defending the fort get # more defence each) like hardware stores, and motels should house people right? and warehouses should increase maximum food by ##
*sends soldier to recruit a lone survivor* -soldier: hey man, do you want to join oure safe haven that consists of every building in this town except for this one? -survivor: nah man, im cool
ive got an idea for an update, cars, everything from a jeep to a 50 cal on a armored Humvee. survivors may bring them and you can find them when scavenging places(especialy parking loots)