When Burt arrives back in town after first attack, Nancy says it's been 11 years since the events of the original Tremors. The first movie takes place in 1989 and not its release date of 1990, which would be 12 years.
When Burts Ford Explorer sport trac is first seen it has the factory rims on it, however when it goes over the cliff and explodes when the camera shows it it has hubcaps not rims and appears to be a totally different make of automobile.
When Burt is getting gas, he removes the rock from the top of the box that holds the cash. He puts his money in and sets the rock next to the box. In the next shot, the rock is on the box. Then, in the next shot, he is putting the rock on the box again.
When Burt, Jack and Jodi are in the port-a-potty hiding from the Ass Blasters, someone locks the door and 'IN USE' is showing. After they decide their plan, they simply open the door while it is still in the 'IN USE' position, meaning it should still be locked.
At the very end of the movie, when Bert is telling Melvin that the whole town would rather have El Blanco than him, Bert's car door is open. As he goes to pull away, it's closed, even though we never heard it shut.
When the FDA geologist wandering the desert dies from a creature attack, the wounds on his back are bleeding obviously orange blood. This is due to the fake stage blood mixing with the fire extinguisher's CO2 that covers the man's body, causing a chemical reaction that turns the stage blood a bright orange.
At approximately 28:37 Burt is testing his remote control dynamite buggy the ground under it dips and springs back indicating a thin piece of plywood under the small gray gravel where everywhere else is just dirt.