I think I first saw this movie about 5-7 years ago on the old HBO. The movie is about a family of 3 (mom, dad and daughter) who live underground because of a virus which have infected their town. There are 3 different plotlines going on at once in this movie:
1: The first main plotline is the parents telling their daughter about how there are these monsters with green eyes which glow in the dark, who are very quick, and they move in large groups. It turns out that they were describing the military taskforce who ends up finding them and killing the dad, and when they are about to be killed both the mother and daughter gets “super powers” and become feral and kill the taskforce and then they find rest of the city’s population hiding in a cave.
2: The second main plot is a flashback where you see the family acting their normal everyday live until suddenly the police showed up. (I believe they show the family escaped and how they find the bunker and thats where the flashbacks ends.)
3: the third side-plot is when the family finds a rat which is eating their rations which is where we first see their feral nature (I believe)
So, these 3 plots are switching back and forth and the viewers are misled as to who the monsters are as a plot-twist. This is all I can remember hope this helps. And thank you for the help.