Health is an effect that allows a player to take multiple lashings of damage from foes or the environment. It is of a limited quantity and can generally only be replenished through seeking first aid kits or by waiting a certain amount of time behind cover to recover. It is often visually conveyed to the player by either a bar that decreases in length as health is depleted, or by a number on the HUD representing the percentage remaining, or the number of hit points left. Some games such as the Call of Duty series choose not to show a distinct amount of health, instead displaying the well-being of the player through means augmented within the gameplay such as an audible heartbeat and loss of colour from the screen. Health is often supplemented by armour; a similar quantitative device to represent how much more of a beating the protagonist may take. Certain games combine regenerative health with non regenerative health, in that they allow the player to heal to a point, after which, they must use some form of item that recovers lost health. Some health systems include injury.
Note that there is a separate hit points concept for games that don't call it "health".
Double Life Bar/Hidden Life Bar
This entity is most often seen when encountering bosses within a video game. The player is chipping away at the boss life bar, getting it very near the empty mark. The player will deliver what they see to be as a death blow to the aforementioned boss character, only to have said boss character's life bar refill instantly, often times in a different color to signify the player has reached the second stage of the boss fight.
Red Cross censorship
The games are no longer allowed to use the red cross symbol in hospitals and healing items due to the International Red Cross and Red Crescent Movement's censorship.