Plot Prediction
Potentially way off mark, but...
It's a "zombie movie" from the zombie's point of view. People die, but then they come back to life. They don't remember their past, although some are driven insane and become murderous. Some kind of toxin/bioweapon, and the government/company is tossing the bodies in the pit after they "die"... but then they come back.
The woman in the trailer who is playing with the collapsing zebra toy gives it all away.