The camera angle meant to show Arte's perspective through the spyglass is inconsistent with hole that he drilled. Also, given the architecture of large houses in the 19th century, he would have had to drill through the floor and the ceiling (large beams in between), but the drill doesn't appear to drill deep enough, nor does the spyglass extend far enough to have gone through floor, ceiling and beam in between.
When Dimas bends the bars of the cage where Artie (as Dr. Gentry) tries to escape (or protect himself from Dimas), the bars wiggle like soft plastic or rubber. Also, when Dimas bends the bars back, they return to a perfectly straight state - in reality, they would have had kinks in them from being bent back and forth.
Opening sequence: while the sound of the white dog growling as West approaches is heard, visually, the dog is cowering away from West.
Off camera system someone is smoking, you can see the smoke drift in front of the camera. When where Artie is talking to the Senator. At about the 39 minute mark.