I did cringe a bit with the ladder/fence climbing zombies and when the one used a brick or rock as a tool, but otherwise I think it's been very well done.
They're going by Night of the Living Dead rules. Bill Hinzman used a rock to break Barbara's car window, and some of the zombies were trying to climb to the second story of the house.
Which would be great if this was a NOTLD series, but it isn't!
Besides, the first episode made the zombies REALLY smart in zombie terms. Right from the very first scene... a zombie girl is walking along holding a stuffed animal (that part is accetable, she could have been holding it when she died). She drops it, but instead of just going on, like a normal zombie would she frikkin, stops, looks at it and picks it back up! In a later scene, a zombie returns to here own home and tried to open the door by turning the knob! The only reason she can't get in is the door being locked.
No zombie since "Bub" has been this smart and he underwent special training. Nearly every zombie in this tv series so far has been really smart.