When you wake up and you can't find anyone else and can't even remember much... that is a horror scenario. It's also a scenario that you can take a lot out from and make a lot from. The tension is high, the questions are there, but the answers will not really be satisfying overall. Which is a shame considering this was made by the director of "Them".
Having kids in the main roles makes this sort of relatable and even more fantastical. But it also gives it some limitations and it doesn't really have much to do with the acting abilities. There is not that much to play around with. And even though there is a vast amount of space (for a period of time that is) it still feels like it has long spaces of dragging and not moving forward. It's OK, maybe feels even better if you are in your teens and have some of its angst... otherwise you may feel you wasted more time on this than was necessary.
Review by kosmasp
from the Internet Movie Database.