Good idea but badly executed.
The Happening, Bird Box and this. These themes of losing a sense to stay alive in an apocalypse is a pretty cool idea, however they all feel a little 'dumb' at times.
Here in this film we actually have a fairly easy creature to destroy. You could easily set traps, lure the monsters to a sound far away and BOOM! remote blast them.
With the study of the family about to have a child, there seemed to be some pretty bad dumb mistakes. We're shown that living near a waterfall provides a great deal of security, even just to sleep there with security doesn't sound like a bad idea to me, but nope let's instead live in fear of the slightest accident which surely will happen.
I wouldn't have minded to see this film take on a more 'World War Z' type vibe where the military still have some control and are working on ways to attack them. It's just pretty unrealistic in a post apocalyptic world that only random civilians are left alive. Could we not kill them from the skies? I mean if we had the chance to put out newspapers alerting to what they are and how they attack (via sound), it doesn't sound like they wiped out 99% of humanity in 2hrs...
The military have nuclear bunkers etc, there would be key government figures still safe for sure, and if Emily Blunt can kill one with a shotgun after it's had a bit of a headache... I'm some marines could do a good job with some sound traps.