When Johnson is being chased by Sherbourne on motorcycle, a station wagon by the side of the road is passed at least twice.
When Johnson is being chased by the motorcycle cop, the siren comes on momentarily and then goes off several scenes before it finally comes on to cause the crash.
The wires can be seen that are moving the floating alien creature as it comes through the doctors window.
During the murder of the first victim. Watch the right hand of the dead teenager twitch as a Fly lands and walks about her arm. If your watching what Paul Birch is doing you won't notice this.
Near the end Nadine is told to step inside the transmitter beam and she does, despite being unable to earlier with Jeremy.
Not only can you see the boom microphone, but can see its shadow on the wall when Nadine talks to her boyfriend Harry, at the kitchen table.