Continuity mistake: West tosses a small grenade at the French doors. We see it hit and explode without breaking a single pane or crosspiece. It just makes smoke and blackens the surface. After a shot of West and Gordon, we cut back to the door and it's now a broken ruin with no glass and the wood framing destroyed. Delayed action bomb?
Continuity mistake: West and Gordon drag Day from the haunted house, prop him on the porch and turn away. When they turn back, they're stunned to see that he's aged 30 years. But if you look closely, you can see that the man they prop on the porch is already gray-bearded and shaggy. So why were they surprised?