When Abe is about to reveal to Aaron how the time manipulator works, they are standing in front of the white truck. The four-way hazard blinkers are blinking, then the camera cuts to another one. At that point, the blinkers are off. Then they are on again with the third camera change.
When Abe is first telling Aaron about the box, he starts by explaining that the Weeble was accumulating years worth of protein build-up every few days. He later explains that anything in the box must experience subjective time. That is to say, to go back one minute, you must spend one minute in the box. This means that the absolute most amount of time the Weeble could have experienced is only twice the amount of time the box has existed and been turned on.
During numerous takes the director, Shane Carruth, mutters
"cut" under his breath. According to the DVD commentary, this is due to their extremely low budget which did not allow them to "waste" film. Carruth notes that a total of 80 minutes of usable footage was shot; the final film is 78 minutes.