SCREEN

Zombie Scale
Indicates whether you're closer to zombie or human.
Food Gauge
Shows how hungry you are. The gauge depletes over time, and you'll start to move slower when it gets too low. If it reaches zero, then it's game over.
Water Gauge
Shows how thirsty you are. The gauge depletes over time, and your vision will blur when it gets too low. If it reaches zero, then it's game over.
HP
Shows how much HP you have. The bar goes down when you take damage from enemies, and if it reaches zero it's game over.
Energy Gauge
Goes down from performing actions such as attacking, dashing, and gathering resources. When it reaches zero, HP will be used instead...and THEN it's game over.
Time
The current time. The next day starts when the clock hits midnight.
Day
Current day of the week.
Time of Day
Shows the progression of day to night.
Mini-map
A map of the immediate area.
Current Mission
The objective of the mission currently in progress. Press right on the D-pad to switch between other active missions.
Item Slot
Shows your currently equipped item. Press the X button to use.
Equipment Slots
Shows your currently equipped weapons. Pull the right trigger to attack, or press down on the D-pad to swap weapons.
Action Prompt
Shows any available interactions. Press the A button to talk with people, investigate things, and more.

INVENTORY	An overview of all the items you have on hand. Open it to equip weapons or use items.
SKILLS	A list of your skills. Use the left and right bumpers to swap between categories. Depending on the skill, you can also press the Y button to see details on the items that can be crafted.
MISSION	Shows all missions that have been accepted, completed or otherwise. Your currently active missions will be framed in white.
OPTIONS	Allows you to change a variety of settings. Can also be used to return to the title screen.
MAP	See a map of the entire area you are currently in.

The map doesn't just give you an overview of your current area, but also includes a number of helpful icons for your convenience. If you aren't sure what an icon means, you can toggle the legend key with the X Button.