Realism Mode Details

Realism Mode, says Kim Swift (Left 4 Dead 2 level designer), is for advanced players only, a way to make the game more interesting for players who don’t feel challenged by the expert difficulty level.
Turning on Realism turns off the glow that normally haloes players and special infected creatures. “Communication becomes really important,†said Swift. “Players need to stick together.â€
The game is designed such that getting separated from the three other survivors is life-threatening. The glow normally helps players find their way back to the group, or helps find team members who may be incapacitated. Swift said that when players need help in Realism Mode, they need to be able to accurately and clearly describe where they are in the game environment so that the other players can locate them.
Health and items “don’t glow until you are right on top of them,†said Swift, which means that while regular gameplay might involve dashing from one safe area to another, in Realism Mode searching and exploration are essential to survival.
Swift said that Realism Mode also affects damage, so chest shots on the infected are not as effective, and players need to make head shots. “Just like in the movies,†added Valve’s Yasser Malaika as his Left 4 Dead 2 character killed a zombie that was about to finish off my character.
There are five campaigns in Left 4 Dead 2, each with multiple levels, and Swift said that all of them can be played in Realism Mode. And it’s possible to scale down the difficulty to easy in Realism, for those players that want to see what it would really be like to be in the midst of a zombie apocalypse, but don’t want to be killed too quickly.

Dang this is gunna be insane, awesome!
The tank must be hard to kill in Realsim mode.
@Muffinz
If you read it right, it takes out all special infected:/
@Jakerzz
I don’t think the special infected count as ‘realism’ lol
@Jakerzz
Oh
I cant wait
@Jakerzz
What the heck are you talking about? Special Infected are still in Realism mode, dummy.
@Tyler
Try reading all of it.
Turning on Realism turns off the glow that normally haloes players and special infected creatures.
@Tyler
Oh wait nvm your right. It says it turns off the haloes around the special infected.
@Tyler
What the hell are you talking about?
Turning on Realism turns off the glow that normally haloes players AND special infected creatures.
Go back to school:\
umm tyler..
What the hell are you talking about?
Turning on Realism turns off the glow that normally haloes players AND special infected creatures.
Go back to school:\
It says that you can’t see teammates, items, or special infected as easily. Being that the glow that is usually seen surrounding them is gone. I like it, sounds like a challenge.
i hope they have that on the demo
That would be awesome, but I don’t think they will. Just my guess.