When the 'Cuda wrecks Reggie is holding the double shotguns. When Mike cuts Reggie down he also grabs the two duffel bags which are the only things they carry away from the wreckage. Later in the movie the shotguns come back.
When Reg hears Mike in trouble, he puts down his guitar and runs upstairs. The rocking chair which was next to Reg has now gone in this shot, the rack of utensils by the fireplace (poker, shovel etc.) has switched which side of the fireplace it is on, and the logs by the fireplace have changed completely.
After the 'Cuda hits the rock, the car takes off and lands on its roof in the grass with the exhaust system intact. When Mike gets up off of the pavement, he walks past a burning tree with a tail pipe in it, and the 'Cuda is now on the pavement.
When Reg and Mike jump out of the bedroom window to escape from the dwarfs, in a wide-shot the white window framing on the sides of the window is broken off. But in a close-up of the dwarfs looking out of the window, the white wooden framing has reappeared on the sides of the window.
When Reg and Mike break into the hardware store for tools, Mike puts two torches on the shop of the trolley, and they are side by side, but in the next shot they are spread apart, either corner of the trolley front.
When Mike is in the room with the female cadaver, after he looks at the girl and walks back towards the door one of her legs moves when she's supposed to be dead. This happens just before the camera shot is fully on Mike by the door.
When the priest looks at the door while hearing a banging noise the door chain lock is in the locked position. When he later approaches the door the chain is hanging loose which he then places in the locked position.
As we see the view of the sphere soaring through the air, as Liz and Mike struggle with one of the crematory henchman, on the floor you can see two white tape marks which are not there in any other shot.
When The Tall Man abducts Liz, throwing her into the back of his hearse and then drives away, Mike and Reggie hop into their car and chase after him, hoping to rescue Liz. When they are along the side of the hearse, they see The Tall Man driving and Mike tells Reggie : "Well, shoot the fucker!". A bad idea since Liz is in the back of the hearse and would face certain death if the driver was killed and no one was left to steer the hearse.
When the Tall Man carries Liz out of the pillar room to strap her down on the embalming table, the pillars are seen in the background. Reg's feet should be visible, hooked around the right one, preventing him from being sucked completely into the alien world. No feet are visible.
When the sphere flies towards the mortician and pins his hand against the wall, you can easily see the blades are actually stuck in the wall between his fingers and not lodged in his palm which the scene indicates.
When the Tall Man's sphere lands on one of the henchman's hands, pinning it against the door, the long thin black wire which guided it to his hand is visible attached to the sphere, running off-screen.
When Mike and Reg are sucked through the pillars, there are two shots of Reg in the alien world. His feet, which should be hooked around one of the pillars, are visible in the shot, wholly in the alien world. Reg is also lying on his stomach, with his feet side by side on the ground, when his feet should be vertical, hooked around the pillar back on his world.
As Reg fights with one of the baddies with the chainsaws, as the baddie take a swing with the chainsaw he misses and cuts into the wooden door. You can see that a vertical cut has already been made in the wood though, to help the chainsaw get in and cut.