Shyamalan's Most Mature Work to Date [mild spoilers]
Had this been made by anyone other than M. Night Shyamalan, the conversation around the film would be very different than what it is. He's become pigeonholed as the "twist ending director," and now everyone approaches his works waiting to see "what really happened" after some final denouement. However, Shyamalan's greatest strength has almost never been the endings of his films. Where he excels is at building, and maintaining, moments of suspense, and creating visceral dread in his audience, and that is so often forgotten as viewers attempt to guess how the film will end.
"Old" doesn't have any sort of twist at the end, and I fear this leads many viewers to judge the film solely by how surprised they were after the film was over. There is a sort of reveal, where we learn why something we already know about was done, but there is nothing shocking about it, and we aren't forced to reevaluate any notions we'd already formed.
The power of this film is in its unrelenting tragedy. I think it will be especially disturbing to any parents of young children, but everyone can relate to its themes of mortality, and what, if anything, is the point to a life. Once the characters hit the beach, "Old" never lets up for even a brief moment, and we're forced to watch lives disintegrate and dreams die at breakneck pace. It's disturbing, it's poignant, but most of all, it is profoundly, and unabashedly, sad. This is not only Shyamalan's most mature work, it is also his most heartbreaking.