Sometime I imagine what does my character look when they are wounded.
It always indicate red color surrounding that pertaining for the blood.
Then after seconds and minutes of hiding the red screen gradually changes to a normal vision again.
This is one of the general ideas of game developers about shooting games, where it is effective for new and old players to know their life point or health bar is near to death.
Sometimes it's annoying because you want to shoot down the enemy who did this just to let them know what is the feeling of having a red screen.
