When the 4 time travelers run into a cave, they are rushed by the mutants who are blocked by an invisible force field. After they run off, the time travelers approach the invisible wall. You can see a reflection of a jacket on the wall, revealing that it's just a pane of glass.
When the final montage speeds through the whole story again, the instant printout of Alpha Centauri IV is misaligned in its frame. It was perfectly aligned the first time it appeared.
At about the 5 min point, one scientist says "Standby switch". In the close-up on the hand of the woman scientist, as she is crossing her fingers, the switch is already in the on position and, when the command is to switch on, she switches it to the off position.
When the characters return to their lab, they find they are unable to move any matter. Yet the characters are still able to move and breathe. If they were actually unable to affect any matter, as they clearly establish and go to lengths to explain, the air would not move out of the way when they walked nor would it move in/out of their lungs.
When the time travelers are in the lab (116), they realize that all objects are frozen in time and cannot be moved. However, when they first returned to campus, they entered the building housing the lab. The first door they try could not be opened. However, they then try and do open a second door (115). Both doors should have been frozen in time.
When everyone returns to the campus, and everything is moving so slowly that it seems to be stationary, the tops of the trees are still moving in the breeze.
When the four 1960 earthlings return to their lab to find themselves frozen in time, the frozen Steve Franken blinks his left eye.
When the mutants chase the scientists into a room, they barricade the door with furniture, but the door opens the other way.