When the kid are looking for the 'main switch', Kyle runs to help his mom who is trying to help his dad who is trying to climb out of a shaft. He has a dead lamprey over his shoulder to keep the lampreys away as they don't like the scent of their dead. As he gets to his mom, he throws the lamprey down the shaft, but when his dad is out of the shaft, and as the scene moves on, he still has a lamprey on his shoulder.
In the first scene the van has a Michigan front license plate. Michigan doesn't have a front license plate.
This takes place in Michigan.There are no mountains of any kind in Michigan like the ones shown in this movie as shown when the game commissioners are walking by the lake.
The opening shots show palm trees in Michigan.