Other mistake: When the things clean Mom's dress, the purple goo goes directly onto the couch on the right side of the room. After Conrad asks about the couch, and the camera pans over to the now filthy couch, look at the end table and lamp. They were in the direct line of fire, but didn't get touched. Also, look closely at the lamp. It appears to be a piece of thin lumber cut into a lamp shape.
Other mistake: When the Cat is using the periscope to look at Nevins, the range on it reads between forty-nine point two meters, and fifty-two point four meters. These distances translate into just over one hundred sixty-one, and one hundred seventy-one feet respectively. The kids and the Cat were no more than about fifty to sixty feet at best away from Nevins.Movie Nut