When Walker Stevens is in bed and Rex is talking to him, the shadow of a boom mic is persistently visible before Martha joins him and the monster spies them through the window.
After the monster trashes the drugstore and walks out to the right side, a shadow on the left side moves around on the floor.
In one wide shot, the creature wears tennis shoes while returning to the lab.
The corpse breathes during the morgue scene.
When Zaat drinks the medicine in the pharmacy, you can hear the fluid draining from the suit on to the floor.
When the monster kills the family in the boat, it chases the wife toward the beach. In one shot, the monster stands still for a few moments, clearly waiting for its cue before resuming the chase.