could be an 8 if....
...they edited it down to 30 minutes.
It was eerie enough in places and the sound design was done very well. Maybe look at old twilight zone episodes to see how to efficiently tell a story in 30 minutes. Well that is after a story to tell is developed.
Don't know that interminably wandering around with alien sightings constitutes a story. Yeah I know there are are suggestions of a virus, alien/human co-operation, a "find the missing friend thrown" in there but still no story.
In summary, figure out a story line (hint: beginning, middle and end, conflict to resolve, protagonists and antagonists that do or decide stuff), and tell it in 30 minutes and it's at least an 8.