In the opening scene the windows of the first floor in Dr. Pretorious' house are shattered. A little later in the movie, when the team arrives again at the "crime scene", it is clearly visible, that the window classes are still unbroken.
When Crawford first tests the machine for Katherine and Bubba, it is obviously still night time, but a short time later when he turns it off there are rays of sunshine pouring through the window as if it is late morning.
After Dr. Katherine McMichaels sprays the machine with a fire extinguisher and it turns back on a puppeteer's leg, the rig holding up the Dr. Edward Pretorius monster puppet can be seen behind the puppet.
When Bubba tackles Crawford and they fall down the stairs, for a brief moment just before they hit the landing "Bubba's" face is shown (from the camera at the top of the stairs), and it is obviously a stunt double.