It is a very tense movie because the threat is not obvious, even to the audience. Anybody in the movie could have been taken over by the pod people, leaving the characters in a relentless state of paranoia.
And while the original Invasion of the Body Snatchers already dealt with some disturbing themes, this remake with Donald Sutherland dials up the dark, disturbing nature of the situation.
Anyone who has seen the movie will remember the iconic scene of the main characters encountering a body snatching gone wrong, resulting in a dog with a human face. Invasion of the Body Snatchers is a bleak film, with Donald Sutherland’s character eventually realizing how little opportunity there is for humanity to survive this invasion.
He and the other humans can do their best to blend in with the pod people’s behavior, but they have to sleep eventually, and that will leave them vulnerable to being assimilated.