Miss your shot at an enemy soldier, and you'll probably see him flop to the ground, looking for cover. The buildings, vehicles, and objects look very believable and add greatly to the environment. There are a lot of nice touches. Bodies just don't fall down and die.they often make last-gasp crawling motions. Grenades, rockets, and explosions make realistic looking smoke plumes.
Tracers fly everywhere.
One small gripe I have is with DF's use of lighting in buildings. From the outside, all you can see in open doors and windows is almost pure darkness. I understand that this is trying to simulate the difficulty of urban close combat, but I think it's overdone. Perhaps the 3Dfx patch will address this with more dynamic lighting effects. The sound in DF is simply phenomenal.