When Dean and Sam talk in front of the church with Crowley chained inside, the door of the church closes and opens between shots.
When Sam and Dean have Crowley in the deserted building Dean goes outside to the trunk of the Impala where Sam is retrieving the items needed for Crowley's exorcism. When Dean steps out, the building door is open, when we see the door for the second time it's closed. We then see the door again, but this time it's open.
When Dean paints the demon trap around Crowley in the abandoned church, the floor is visibly wet with standing water. The spray paint would wash away almost instantly, making the trap worthless.