A lot of divisiveness about different ways of reviewing The Block Island Sound will likely boil down to the way a person chooses to interpret its ending. However, for me, the movie already misses the mark sometime before that moment. As a story, it opens in an interesting manner - a small island and a fishing family (or the family of a fisherman) slowly becomes consumed by a strange sound they begin to hear. This blends perfectly with their already numerous personal issues and emotional problems, showing again that living on a small, wind-swept island in the Atlantic might not be the best place for mental well-being.
However, beyond solid acting and good cinematography, the moving quickly loses focus in terms of what is trying to accomplish. Through the perspective of one family member, Harry, we kind of see a descent to madness, irritation with life going nowhere, sleepwalking from hell, and a mystery to be solved. Yet, we get nothing of that, as the movie becomes bogged down in itself nearly halfway in. From there on, the viewers basically wait for someone (or someone else) to die already and give The Block Island Sound some semblance of closure. Expectedly, it fails to deliver that as well. So, the entire experience ends up with an interesting premise in a cool setting for psychological horror, but which doesn't evolve into that cool horror psychological film at all. Instead, it lingers and it then ends in a lingering way.