This was a good movie. As with every other movie, there were gaps that needed to be filled. However, I strongly believe this was an intentional move by the director to get the viewers to fill in those gaps themselves, aka, use your imagination. The people who have left bad reviews seem to have over-analyzed it by attempting to make sense of the plot using logical reasoning, forgetting that it was simply a fictional movie; IT'S NOT REAL! We know for a fact none of these is ever going to happen and that's the fun part. That being said, two observations. First, the theme of blindness/disability could've been explored more at the end where Malorie and the kids eventually make it to the school for the blind. Whether intentional (born with it or have it later on in life, as is the case with the people at the sanctuary) or unintentional (Malorie and the kids having to live blind to get to safety), disability may be a survival skill.
Secondly, I observed that a lot of the negativity stems from the fact that the "creature" is never revealed nor defeated in the end. I felt that way initially but then I thought, evil can't always be conquered, but we can adapt (put on our blindfolds) and live through it. To have shown the creature would've taken away from this deep message. Overall, this movie requires a lot of critical thinking, something that not everyone has the patience for and that's okay!