10 Awesome Movies That Fail In The 3rd Act
5. High Tension
No list of films about self-sabotaging third acts is complete without Alexandre Aja's High Tension - a brilliantly wrought, ultra-violent slasher film which biblically screws the pooch in the final 10 minutes.
For its first hour-plus, this is a tenaciously crafted, white-knuckle thrill-ride in which our two protagonists, Marie (Cécile de France) and Alex (Maïwenn), flee from a sadistic serial killer who murdered Alex's parents.
It's built from basic parts, but the execution is so uncommonly intense, disturbingly brutal, and well-acted, that it's a massive shame Aja steers the story in a genuinely braindead direction in its closing section.
Aja drops a wildly unnecessary clanger of a final twist, that the killer was actually Marie all along, with the murderer we've seen throughout the film being nothing more than a dissociated figment of her deluded imagination.
It's an infuriating revelation because it isn't earned, isn't telegraphed in any clever way, and feels like a cheat because it contradicts previously established information and events.
Basically, the third act retroactively makes the awesome first hour feel like a waste, even though the twist does admittedly have a small but vocal army of defenders.