The plot ruins this film

Rating: 3/10 (22 March 2019)

I understand what was trying to be achieved but it fell flat.
This movie reminded me of movies like the mist or cloverfield. There is this underlying plot of "sci-fi experiment gone wrong" that doesn't get explained. However in this film we get a small but lazy explanation. This came in the form of a text card at the beginning of the film that basically reads "There thousands of tunnels in the world. Who knows what's in them". This was the movies only explanation and setup for a civilization of 6 million clones of people living in an underground tunnel. When the movie ended and it pieced together to be this it made for an overarching plot that was just stupid.
Now these clones did refer to themselves as shadows because they were sometimes forced to mimic the movements of the person they are cloned after. It was weird how selective that was and is very inconsistent in a way that hurt a couple scenes in the movie.
The rest of the movie is just those 6 million clones coming out of the tunnel and killing the person they are cloned after. Once they accomplish that they hold hands and form a line stretching across the United States. And no I'm not kidding, this is exactly how the movie ends.
The only redeeming qualities was good acting, good music, and decent humor. However, none of that can fix a terrible plot that ended with an nonsensical twist. Like a sour cherry ontop.