The inopportune solar eclipse takes place after a night with a full moon. This is impossible; during a solar eclipse, the moon is between the earth and the sun, in a new moon phase.
A solar eclipse does not occur in that speed. It takes quite a long time from the beginning of the eclipse to the end. Besides that, even moon moved that fast, it would have passed in the same speed, it wouldn't come fast, waited at same point and left fast. Lastly, the moon entered the eclipse from left side of the sun and it also left from the left side.
When one of the vampires are thrown on the horn (mounted on the grill of the Cadillac), one of the horns move with the body, revealing it is not attached to the car, but to the clothing of the actor.
When Jesus is fighting with the female vampire in the motel's bathroom, there is a shot of him throwing her at a mirror. It makes sense that the vampire does not have a reflection in the mirror, however, in that shot the actual vampire is also inexplicably invisible. It is obvious that Jesus is merely grabbing thin air (in reality as well as in the reflection), and that the mirror spontaneously breaks without anybody touching it.