Pretty Cool.
You know what would be pretty neat? I f that dot fly bit someone, and that someone turned into a roto-scoped zombie person due to the bite. Then it be cool if that person spent the rest of the movie accidently infecting others with his roto-scope illness in the search for a cure to his condition. Anyway, I like how that dot buzzes around the people, and how the people interact with it. Overall, great fx!