Blake fights a boss in The Thing. The HUD shows his health (red bar), currently selected weapon and ammo count (on the right), and his left hand item (in this case flame grenades).
The trust system in The Thing. In this screenshot, Carter does not trust Blake, and will not follow him (top), perform an action for him (left) or give him a weapon (bottom). The only option available to the player is to give Carter a weapon (right). Upon doing so, Carter will trust Blake, and the other options will become available.