Continuity

When Rick and Michonne begin to decapitate the herd of Walkers with the cable attached to two cars, blood and guts accumulate on Michonne's windshield in the close shot, but later in the long shot there are no guts, only dust on her car.

Plot holes

Deus ex machina: Rosita reveals to the others that she has training in explosives. There was never any indication that she had any special skills, and this is something that would have been invaluable for the rest of the group to know, long ago. Still, Rick and the others don't ask what other skills she may have, or what else in her past she may have been hiding from them all along.