HUD

The HUD or Heads Up Display is a graphical interface overlayed onto the screen to give the player information. It includes a cross-hair, compass, hotbar and the hotkey tool-tip.

Compass
The compass shows the cardinal directions relative to the engineer's current facing and also indicates the directions of vehicles with an icon. It also shows the direction of what seems to be a waypoint.

Hotbar
The hotbar is a list of numbered slots, similar to hotbars found in many other games. Placeable entities such as vehicles and buildings can be placed in the slots, presumably allowing them to be selected and placed.

Tool-tip
The tool menu lists several tool icons and their associated hotkeys. It seems to list the following:
 * B - Build
 * Q - Demolish/ Self driving menu
 * F - Flashlight
 * C - Unknown. Possibly an inspect tool?
 * V - Possibly messages or notifications
 * I - Inventory
 * M - Map.

Vehicle Status
This is displayed when the player is piloting a vehicle, and gives information about that vehicle, including its current fuel, and an unknown blue bar.