Population and Population Cap: The numbers by the person icon represent population and maximum population, where the number on the left is population, and the number on the right is maximum population, or your population cap. You can increase the population of Abel by constructing buildings such as housing. You can’t add more people to Abel than your maximum population. Population cap can be increased with buildings like the Hospital and Farms, also by upgrading Janine’s Farmhouse.
Defence: This is the shield icon and represents how well the base is able to defend itself. Only the Defence Tower can be visibly damaged; the higher the defence, the less damage the tower sustains from a zombie attack. You can repair it at the cost of some supplies. The tower contributes half of the base’s defence rating; the remaining half can be accumulated by building other defensive structures.
Morale: The smiley face represents how happy Abel’s residents are. It is calculated by factors such as population, building modifiers and addons, the state of the defence tower and your progress through the main storyline.
Supplies: These are indicated by the Satchel icon, sometimes also called the box icon. Supplies are collected in proportion to the amount of time that you spend running; you will collect about 30 supplies an hour.
Materials: Often called wrenches, spanners or tools, are collected in proportion to the amount of progress you make through the story. Unlike regular supplies, there will be a set number to collect in each mission. You will receive three materials when you first run a mission; this will decrease by one each time you replay the same mission. Again, these are used to build and upgrade buildings.