Goof (errors in geography): Rick is supposedly going south on I-85 going into Atlanta, but that is not the skyline of Atlanta you would see if you were heading south. The skyline is from Freedom Parkway, facing West.
Goof (revealing mistake): The bus that Rick passes while in Atlanta, is not the type of bus that is used in Atlanta by MARTA.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): At the beginning of the episode the deputies establish their roadblock incorrectly. The patrol cars should have been angled so that they point in the direction of traffic. That way if the fugitive tries to run the roadblock the cars will be pushed to the side of the road instead of crushing the officers between them.
Goof (revealing mistake): During the shootout following the car chase you can see elbow pad on the first gunman as he falls after being shot.
Goof (revealing mistake): The M1 Abrams tank is actually one of the few tanks without a "belly hatch." The "M1 Abrams" in the show is actually a different tank mocked up with fake body panels to pose as an modern Abrams.
Goof (continuity error): During the gunfight at the first of the episode, Rick is shot just below his left shoulder, in the back. After he awakens in the hospital, and thereafter, he is shown with a bandage over his lower left abdomen, and there isn't a scratch on his back.
Goof (revealing mistake): When Rick awakes in the hospital you can see that his IV bag is empty. Blood backs up into IV lines when a bag is empty because it forms a vacuum. Rick's lines are blood free.
Goof (crew or equipment visible): Incorrectly regarded as goof: When Rick is on the horse in the city and he sees the reflection of a helicopter, he runs into a mass of zombies. Look closely and you will supposedly see a clean non-zombie guy drinking from a cup in the back left of the zombie mass. However, if you look real closely in the zombie mass in the previous shot before the horse jerks back and the shot after when the hoard of zombies start chasing Rick you will see the same "non-zombie guy" on the left and his face indicating he is actually one of the zombies. You can tell it's the same guy because of the shirt/dark sleeveless leather jacket he's wearing.
Goof (revealing mistake): The tank which Rick hides in is a Cheiftain Mk10. It is a British Army tank designated FV4201, manufactured by Leyland and used by the British Army between 1966 and 1995. The tank in the episode (along with those seen outside CDC later in the "Wildfire" episode) are all painted tan and feature the inverted black "V" which was used to identify Coalition troops during the First Gulf War. This model of tank was never in service with the American Army and as such it would be highly unlikely to see four of them abandoned in Atlanta as depicted.
Goof (revealing mistake): When Rick is backing up the Truck at the construction site he turns his body backwards in order to see where he's backing up the truck, but the camera immediately cuts to the back of the truck showing that the tail gate is down, meaning Rick was looking at an empty truck body.
Goof (incorrectly regarded as a mistake): When Rick finally makes his way out of the hospital, and is standing in the courtyard surrounded by corpses, the building he is supposed to have just left has clearly been abandoned for some years and is partially decaying. The building is revealed to have been partially blown up by the military in a Flashback scene in "TS-19" which accounts for is dilapidated and damaged appearance.
Goof (factual errors): The police leave someone to pull stop sticks off the road so the cars following can pass safely. There is no conceivable reason for stop sticks to cause a car to flip over. They are designed to slowly deflate the tires to prevent loss of control. The point is to slow the fleeing car, not make it crash.
Goof (factual errors): Rick tells Leon to make sure he has a round in the chamber of his gun and the safety off. Leon then chambers a round and makes a thumb motion on the side of his pistol as if flipping a safety switch, and the sound of a switch is heard. However, Leon's gun is a Glock. Glocks do not have external safeties. (The small lever that Leon swipes his thumb over is actually the slide lock.)
Goof (revealing mistake): When Sheriff Grimes picks up the M67 fragmentation grenade in the tank, it has a noticeably blue safety lever. This indicates it is simply a poorly repainted inert M69 training grenade, which are completely blue. An actual M67 is entirely green, with yellow factory markings stenciled on the body.
Goof (factual errors): When Rick hot wire starts the 2010 Dodge Challenger he is pictured using a screwdriver to start the ignition. That model challenger and all new model Challengers use push button start, and also use a Key Fob system that makes the vehicle anti-theft. Without the key fob present and the fact they triggered the vehicle alarm would automatically disable the vehicles fuel delivery system making the vehicle inoperable.
Goof (continuity error): In the scene where Morales and Rick take turns dismembering a zombie with an ax, Morales places a protective helmet on. When he swings downward, the helmet is on, but when he raises his head again, there is suddenly no helmet.
Goof (continuity error): When Morales is handed the axe and begins chopping the body, his face guard falls off on the first chop. It is then on again in the next scene and falls off again on the second chop. Then is on again in the next scene.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): When handing T-dog the handcuff key, Rick Grimes clearly gets blood on his hand after taking the glove off.
Goof (continuity error): When Rick Grimes hands Morales the face guard during the chopping scene, there is no blood or guts on his gloves or face guard, but in the next scene there is blood all over the face guard.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): When Rick and Glenn get to the truck in the construction site they're forced to reverse from a horde of "walkers." Rick looks behind him to back up even though the truck has no rear window. He would have had to look in his side mirrors to see behind them.
Goof (continuity error): When Rick Grimes first meets the group, Andrea pulls the gun in his face. When the camera changes views, her finger is alternating on and off the trigger.
Goof (continuity error): When the group is in the back of the store chopping up the dead body to use its guts, Rick hands the axe to Morales, who then starts chopping the body into pieces. Just before the camera angle cuts in the middle of this, the visor Morales is wearing clearly falls of his head, but is back on his head in the following shot.
Goof (continuity error): When Glenn and Rick are covering themselves in the guts of the walker, Glenn's coat is almost completed covered, except the arms and a bit at the bottom when Andrea gives him the gun. But in the next cut, when Rick begins chomping the corpse again, Glenn is only half covered.
Goof (continuity error): When they are covering Rick and Glenn with guts, Rick hands T-Dog the key to the Merle's hand cuffs. But when everyone runs back upstairs to watch Rick and Glenn in the street, T-Dog is still on the roof with Merle from before, trying to contact the others on the talkie, showing that he has the key.
Goof (incorrectly regarded as a mistake): When Rick and the rest of the group are stuck inside the department store they cover themselves with "guts" because the zombies can smell the living. However, in the second season when they are stuck on the freeway, zombies walk right by them while they are hiding under the cars. This is not a goof. In "Guts" when Rick and Glenn cover themselves, they do it to avoid being attacked once seen by walkers. In "What Lies Ahead", when the group hides under the cars, the walkers don't smell them because walkers can't smell any better than the living.
Goof (continuity error): When Rick and Glenn go after the truck, there is a thunderstorm with rain. Just after it ends the streets are bone dry.
Goof (continuity error): When Rick Grimes is in the tank talking to Glenn he says he has a beretta with one magazine and 15 bullets. Yet the gun runs out of ammo after only 14 shots.
Goof (continuity error): When they dismember the corpse of Wayne Dunlap, Rick hands Morales the visor and an axe. In the first shot Morales's gloves are clean. Then when he puts the visor on his hands are covered in blood. In the next shot they're clean again
Goof (continuity error): In the woods, when Lori is lying on the ground and takes off her blouse, her locket and Rick's wedding ring are on a necklace that is clearly long enough to be stuck under the under the underwire of her bra. In the next shot, the chain is considerably shorter and the locket is resting above the V between her bra cups.
Goof (audio/visual unsynchronized): In the scene where Shane gives Rick four rounds Rick says "thank you" but his lips do not move.