Continuity mistake: When Glenn wakes up we see the door behind him is flush with the concrete, but when he goes inside you see stairs he had to descend to get to the door. There is also no scene in the entire prison episodes where an outer orange door is preceded by steps, they are all flush. Also If you look at the door behind him you see two folding chairs leaning up against the door. When he turns to open the door the chairs are gone.
Continuity mistake: When Carl and Michonne are eating breakfast, and she is rolling up the sleeves to her new white shirt, it is untied. When the scene cuts to her sitting down the shirt is tied at the back. (00:03:20)
Continuity mistake: Glenn demands that Abraham stop the truck so he and Tara can get off, the two male characters then have a scuffle. We can see Eugene in the background standing next to the truck facing right of the camera. When the camera cuts back to Eugene by himself, he's now facing the opposite direction. Also the items in the back of the truck move from left to right. If you look carefully, you can see that the entire image was flipped horizontally.
Continuity mistake: When Eugene sees the walkers come out of the woods, the road is wet. The rest of the scene the road is dry.
Continuity mistake: In the golf club Beth is wearing her new yellow t-shirt and white cardigan. Daryl hits walker blood all over her cardigan. In the next scene she takes the cardigan off and the t-shirt underneath (which was covered by the cardigan) has blood all over it. Back in the forest after this the shirt is clean again. (00:18:20 - 00:21:35)
Continuity mistake: When Mica and Lizzie are running from the walkers on the railroad tracks, they easily outrun them and gain several meters' distance in a few seconds. When they are running to the house, the walkers have suddenly caught up and are directly behind them.
Continuity mistake: In the flashback to the prison, Hershel says "we've been here two months." However, when they show Judith she is shown to be the same age she was when the prison fell (around 9-10 months) If they had only been there two months, and Lori delivered within the first week of being there, the baby should not be very old.
Continuity mistake: Right at the end of this episode when there is another flashback to the prison, the baby is seen many times. Judith is asleep, then the camera angle changes and she is awake, it moves back to another angle and she is sleeping again. This is repeated several times.
No Sanctuary - S5-E1
Continuity mistake: At the start of the episode when Tyreese and Carol are walking down the railroad tracks towards Terminus, they encounter a herd of walkers coming out of the woods. One of the first walkers to cross the tracks is a male walker wearing a burgundy sweatshirt with a rip in the middle. When gunfire erupts at Terminus, the walkers turn their attention towards it. In the next shot when they start to head towards the sound, we see the same male walker now in the middle of the herd yet to cross the tracks, next shot after that, we again see him at the front of the pack.
No Sanctuary - S5-E1
Continuity mistake: Near the end when Rick thanks Tyreese, the cabin door is open after Tyreese had closed it as the group walked up. In next shot it is closed again.
No Sanctuary - S5-E1
Revealing mistake: When Sam has his throat slit, the location of the wound does not correlate with where the blade was shown to be slicing the skin.
No Sanctuary - S5-E1
Character mistake: When Gareth is questioning Rick about what was in the bag he hid in the woods, Rick replies a .44. Rick is referring to his Python, which is a .38 or .357, not a .44.

Continuity mistake: When Beth is looking for a key in Officer Dawn's office, she encounters Joan lying dead in the office from bleeding out, apparently from suicide with a pair of surgical scissors. Her left hand is covered in blood. But when Officer Gorman enters the room and Joan starts to turn into a walker, the blood on her hand has disappeared.
Factual error: In the scene at the fire truck, Abraham uses the deck gun to kill walkers. However fire truck water pumps are powered by PTO from the engine, which isn't running.
Continuity mistake: Maggie pulls the ladder from the rear of the firetruck, but in previous shots the only ladder on the firetruck is hung on the passenger side.
Visible crew/equipment: You can see the casting directors on The Bridge behind Carol and Daryl wearing lime green vests. Then below The Bridge, you can see people driving their cars and a person walking in the parking lot. (00:26:57)
Continuity mistake: When Daryl is driving the hospital van, it shows that he is going to land upside down, on the vehicle's roof, when he drives off the parking garage. In the next scene, the vehicle lands on its wheels, as if it has done a complete front flip. (00:30:00)
What Happened and What's Going On - S5-E9
Continuity mistake: Tyreese, Noah, Rick, Glenn and Michonne all go to see Noah's old base in search of his family. Tyreese gets bit, and they begin to run back to the car. Except for one tiny clip, Daryl is running alongside them, even though he was with the other half of the group. (00:33:15 - 00:33:40)
Revealing mistake: After it starts raining there is a shot looking at the road in The Distance. Notice how the rain is only falling in a small area and stops just beyond where the group is at. The road is dry from there on out.
Continuity mistake: Gabriel burns his collar while eating at the side of the road, however when trying to stop the barn doors opening in The Storm it is back again.
Answer: Walkers are attracted to noise, they can tell who's dead and who isn't dead, in S1 when Rick and Glenn cover themselves in walkers' guts they're able to get far by walking through the herd of walkers because they smell like they're dead, but as soon as the guts get washed off by the rain the walkers immediately attack them, if you draw attention to yourself they will attack you which we've seen that many times throughout the series that it's not always successful. Whether you're covered in guts hiding under dead corpses or under a car.