I was on a train with my sister when I wrote the beginning of this, and she said the most epic thing when I described the zombies.
I said, "They still have brain functions, but lost the ability to speak, and can't think of more than one thing at the time." And she said, "So, they're men." I laughed so hard xD

Based on a true story... Meaning that this is how the zombies act when I play L4D2 x3

A hysterical, roaring laugh pierced the darkness. A Jockey ran past the group, in which every single zombie raised his head. Their vision was weaker than their rubbery bones, but their hearing was sharper than a bat's. If a Jockey was hunting, it meant intruders were near. Intruders always hurt them. Killed them. And, they were food.

Eating another zombie was gross. The meat was rotten, the bones were rotten, every single organ was rotten. The infection was cruel. No, a fresh human was so much better.

Shots could be heard in the distance. But distance didn't matter. They were quick. The night was cold, but their flesh did no longer react to the temperature. They ran, only capable of thinking about one, single thing at the time: Kill the intruders. Maybe they would think about eating them afterward.

4 humans were shooting wildly at the horde surrounding them. A zombie's head was blown off, and the one standing next to it stopped attacking and stared at the body. Unable to express any emotion, it just stared until it was shot itself. They were brothers.

The humans cleared the area, and continued down the road. A single zombie was leaning against a car, the remains of its last meal leaving its body. It looked up, not caring about the liquid still dripping from its mouth. Seeing the humans, it ran to attack, only to be shot on the way.

A Witch was crying. The humans turned off their flashlights, and sneaked forward. She didn't notice, her grief overpowering her again and again, her sobs drowning every sound near her. One of the humans slipped and accidentally fired a shot in her direction. The Witch looked up and screamed, extending her long, bloody claws. No more than a second later, the human was lying helplessly on the ground while the others shot at the Witch, cursing and jumping to avoid her slashes. When she was finally dead, the human was helped up and bandaged by its comrades.

All the time, a dark, crouching shadow had been stalking them, not sure when the time was right. The want to attack was strong, but not overwhelming, leaving the shadow time to plan. Catching one of the humans off guard, away from the others, was better than attacking now and get killed right away. It growled loudly. The humans turned around at the sound, but saw nothing but shadows. They walked closer to each other. All jumped as another horde howled and came running towards them, led by a Charger. It barged through the little group of humans and pushed one of them far away, grabbed him and slammed him into the ground again and again. While two of the others ran to help, the shadow crept closer to the last one. Growling again, it prepared to jump, alerting the human.
"Hunter!" was all he could say before being pinned down and clawed in the chest with violent power and speed. Several seconds passed before the rest of the humans came to help. The Hunter was pushed off and the human got back up.

A few houses away, a big, fat zombie was waddling among the normal ones. In its huge belly, a large amount of bile was threatening to burst its thin skin, but it was barely holding out. The Boomer walked around a corner, and saw the group of people. It waddled back around the corner, and waited, thinking the humans would come toward him. He would vomit on them, and the other zombies would, in their eager to find the source of the powerful smell, quickly dispose of the humans, and they would be rid of them, no more of them dying.
But the humans didn't come. The Boomer still waited, and suddenly heard shots from behind him. Before it could turn around, its thin skin was ruptured by bullets and it exploded with a loud bang, spreading bile in a circle around the remains of its lower body. The other zombies ran to the corpse, ripping it apart, dipping their clawed hands in the bile, and not noticing the humans, who carefully shot each and every one of them.

On the roof of a nearby house, a tall zombie with tumors covering its left side and long tongues sticking out from not only the mouth, but also the out the back of its neck and shoulders, were lurking around, one minute following the humans, the next turning around, as if it changed its mind. It finally decided and crawled onto a higher building. A car alarm went off in the parking lot across the street, and a horde came running towards the humans. The Smoker swallowed its tongue and spat it out, shooting it towards the nearest human. The tongue tangled around him, and dragged him towards the building and the zombies. For a second he was struggling, but the pressure of the tongue soon constricted him. His back hit the wall and scraped against the stone until the Smoker stopped pulling, letting the human dangle a few feet above the ground, just in reach of the other zombies. The other humans came to help, but were blocked by a pool of acid suddenly in front of them. A loud hiss came from behind a car, where a Spitter was running back and forth. It spat again, acid flying from its long neck and dripping from the remains of its mouth. A bullet hit its head and stomach and it fell over, acid oozing out and dissolving the corpse. The three humans looked for the Smoker to help their friend, but could only barely see it, and missed several times before hitting it. A cloud of smoke appeared around the Smoker, its tongue quickly retracted and let go of the human. He fell to the ground, but got up and received a small, white bottle from his friend.

Between some trees, two zombies were arguing, roaring, crying and hitting each other. Another stood beside them and watched, not really noticing what the two were doing. Hearing voices close by, it slowly turned around, its blank eyes suddenly came to life and it ran towards the humans. It came close enough to grab the barrel of one of their guns, but was shot soon after. A lone zombie does not stand much of a chance against four humans. The two others didn't notice before they were dead.

A loud roar suddenly broke the silence of the dead town, and a huge, muscular zombie ran towards the humans. A hundred feet from them it stopped and buried its hands in the ground, ripping a large piece of road out and threw it at them. The humans split up to avoid being hit, and one was surprised by the Tank, who send him flying far away from the others. A small horde appeared, having followed the roars of the Tank. Struggling to fight the regular zombies and also avoid the big one, bullets were flying, some even hitting the humans. While the zombies fell like flies, the Tank stood ground, sending more of the road towards them. Bullets hailed onto it, seemingly without hurting it. It had trapped one of them against a wall and was pounding him again and again, while the others desperately shot its back, two of them running out of ammunition and changing to other weapons. Finally the Tank showed signs of weakness. It hit one final time, and fell backwards, landing heavily. The humans helped their friend up, and walked into a building, where they barricaded the door.

This one was fun to write... But I feel it's weird, writing about something that every player already knows and have probably experienced... Oh, well