Explanation..? No

Well, there were a couple unique, interesting elements about the zombies in this movie:
- They stand around motionless sometimes, as if captivated or brainwashed.
- Somehow they can erect large towers, which look interesting/mysterious.

These are the only "puzzle piece" elements of the movie, which, as viewers, we'd normally assume would be somehow explained, at least in part, by the end of the movie, but unfortunately they are not. We never learn why the zombies erect these towers, nor do we learn how they actually go about erecting them. We actually don't even know if the zombies built them at all, because we never see them physically stacking anything up, though we do see one zombie standing motionless while holding a chair. Also, we never learn why the zombies stand around the towers and stare at them.

This seems to be a problem with a lot of Netflix movies, at least the ones I seem to come across. The movie will introduce interesting element(s), and as the viewer, you think, "Wow, that's interesting! I'm looking forward to when they explain (or at least hint) the explanation for this!" ...But then they just never do.

The acting is pretty nice, the pacing is good, but completely unexplained elements is lazy, because it's just cool/unique for the sake of being cool/unique.