Barney's tool belt disappears and reappears between shots while he is working on the remote control car.
At around 7:20, when Rollin and Willy arrive at David's cell dressed as priests, it is shown that the far end of the bed, opposite the door, is only an inch or two from the back wall. Around 8:07, when Rollin enters the cell, the other end of the bed, without it having been moved, is shown to only have a couple of inches from the front wall with the door. Around 9:40 when the magnetic rods are attached to the back wall to hold the fake wall panels, they are shown to be a little over 12 inches. There would not be enough space to have the bed fit between the fake back wall and the front wall when the distance is now 12-15 inches shorter.
Barney's remote control would not have worked as shown. The steering was all the way left or right with no subtle control. He was also too far away from the car, apparently a half mile or more, to control it around the curves since the car would be hidden from him.
At about 9:30, Jim removes a brick from behind the painting, revealing a wall made of bricks that are 3-4 inches thick. Two minutes later, when Jim pulls the box out of the brick wall, the "bricks" are really just a half inch thick panel with a hole cut out. The edges of the plaster have changed as well.
Much of the time that Barney was steering the car remotely, he was looking down at the box rather than at the car. He would not have been able to make the precision control necessary to steer around the curves without looking at the car.
When Jim picks a lock, he actually has a real lock picking rake, but no torque bar. Both are required.
The newspaper in Spanish has "MANANA" instead of the correct spelling "MAÑANA".
After the two foreign agents are knocked out the Police chief leaves a policeman to watch over them while the others chase the remote control car yet Willy drives in past the policeman to pick up Barney and Rollin and no one questions him.