Continuity mistake: When they crash their truck Steve jumps out of it. The truck is quite dusty and Steve's hand slides on the side of the truck leaving a mark in the dust. Later when Kenneth jumps out of the truck you can see the side has been wiped clean, removing not only Steve's mark, but a whole area of dust. (01:33:50 - 01:34:20)
Continuity mistake: When the gang of survivors goes to Andy's gun shop, one of them shoots a zombie and he proceeds to fall on his knees. The scene cuts to the gang and then to the charging zombies and the shot zombie falls again.
Continuity mistake: In the scene where the remaining survivors are on Steve's boat and Michael stays because he's bitten, the sun changes positions. It goes from being morning to afternoon.
Continuity mistake: At the birth of the zombie baby and the shoot-out, the pregnant girl gets shot through the left eye blowing her eye socket apart. Afterwards, the main blonde girl surveys the area and now the pregnant lady's left eye is undamaged.
Continuity mistake: At the very beginning, when Luis attacks Ana, she escapes into the bathroom and falls over into the tub. The rug on the floor is folded back in the shot from the top, but it is flat when Ana steps out of the tub.
Continuity mistake: In the opening scene after Anna's neighbor is hit by the ambulance, his body is visible lying in the street. However, when Anna is driving away you cab see the street through her car's rear window and the neighbor's body is nowhere to be seen.
Continuity mistake: When the group goes to rescue Nicole from Andy's shop it it is evening, when they return and must evacuate the mall it's night, but soon as they clear the horde in the parking lot it becomes early morning.
Continuity mistake: About 3/4 of the way through, CJ is on the roof of the gun shop and blows up a tank of propane to clear the zombies so everyone can escape. The truck that was blocking the door was their only way in and out of the shop. On their way into the gun shop you see two zombies follow them through the truck to the shop's entrance, but when he blasts the propane, somehow I guess they get cooked. My nitpick is that when CJ goes the same path as the others, there is a dead zombie blocking his exit through the truck's door. If the others already went out that same door they would have had to move that burned zombie to get through the truck.
Answer: It was actually explained in both versions that the zombies went to the mall because it was a place of familiarity, a place that they could remember even if they didn't know why.
Tobin OReilly