The players don't get to keep track of health. The DM rolls for all damage behind a screen, so only the DM knows how much health a player has at a given time. This gives a sort of "I don't know how much more of this I can take." feel to the player, while also giving the DM additional responsibilities to describe injuries well enough to his players.

Ex: DM rolls for damage, a warrior-type player gets half his health knocked down in one hit by some big monster.

"The beast strikes you on the temple with his giant club. You're stricken with dizziness, nausea, and no small amount of pain."

The player knows he took damage. It seems substantial. He doesn't know if he could take another hit like that and stay conscious, but maybe he can kill the monster before he takes any more abuse.

The point of this is to make the decision to run, fight, heal, or even try diplomacy harder to make. I want the players to really feel endangered. If they have the numbers in front of them, they can do a numerical estimate and decide what to do from there, which seems a bit like metagaming in my opinion.

Is this unfair to the players or does it add more immersion to the game?

Thoughts and input are requested.