Factual error: From what I gathered, the machine compresses the empty space between matter, which in turn shrinks the object in its path. So the mass of the shrunken object is still the same, meaning the weight is also the same. This would mean that their weight on such a small area would create extreme pounds per square inch pressure on anything they step on, causing them to press through the wood, burrow into the ground, etc. They would probably need snowshoes to overcome this. Plus Rick Moranis could not sweep them away and put them out to trash, since the weight of them alone would easily exceed 400 pounds.

Factual error: During the scorpion/ant fight scene, the ant and scorpion are close to the same size. In reality the scorpion would exceed the ant by many times. The ant wouldn't be able to fight it, and the scorpion probably would hardly notice it was around.

Continuity: When Amy is in the kitchen cleaning, she starts mopping the floor, then dancing with the mop held upside down. The mop starts out wet, but when she's dancing it's dry (either that or she would be getting dirty mop water in her face while the mop is being flung around).

Audio problem: Look at the neighbor's wife while the father is saying, "super glue?" She's mouthing his lines.

Factual error: In the French version of the film, it's written "historie de" in the opening credits (it means "story by"). The proper spelling is "histoire".

Revealing: In the scene where Amy lets Wayne know that breakfast is ready, she presses a button labeled breakfast. There are other items on the box, such as lunch, dinner, and phone. When they show the board flashing the word breakfast, you can see that the word breakfast is the only word the board can display between flashes.

Continuity: The hole in the window keeps changing size.