So, everyone has already summed up most of the inconsistencies with the movie. Stupid family, stupid world, stupid plot twists, etc.

But the thing that gets me the most is that its physically impossible to make the monster unkillable. Not because of the armor plates or whatever, I can suspend my disbelief in that.

But have you ever heard of never being in water when an explosion happens? The shockwave in the water will virtually kill you alone from, say, a grenade for example. The human body is not that accustomed to large shockwaves so thats all it really takes.

Now see, the aliens have a huge sensitivity to sound, they need to be able to have vulnerable parts of their body to detect subtle changes in the air around them through sound.

Now what kind of form is sound? Oh wait its a wave. Wow, you detonate an explosion near them and it would rupture their entire only sense and basically kill them instantly. Has nothing to do with the armor plates.

And no, the armor plates cannot stop shock like that. There is no physically possible way to have armor plating thick enough to withstand an explosive shockwave and be virtually unmoved without it being so dense and heavy that you literally cant move.

The monsters are supposedly indestructible when any form of explosive shockwave should basically be killing them instantly. The military are supposedly "useless" against them when any form of explosive (direct impact or not) should render them incapacitated or dead.