After he is examined by the doctor and while he is pressing the barbell, the towel around Granger's neck keeps changing position.
When Willy was connecting the red jumper wire to two points in the fuse box this would have caused a short circuit. Sparks would occur and the jumper wire would melt from having 240 volts across it.
During the briefing scene, Barney indicates the bee's injection will render Granger unable to move until he is given the "antidote". But when Barney activates the mist and light effect outside his window, the supposedly paralyzed Granger turns his head to observe.
When the helicopter starts, the sound is that of a piston airplane motor starting. The helicopter is turbine powered and should have had a whining sound.
As Granger and Phelps arrive at the scene of Casey's burning vehicle, Kellogg immediately flees. Casey is then transported to the "alien headquarters". Ordered to kill Granger, Kellogg somehow implausibly is able to locate him.