The Piper takes the fairy tale of the Pied Piper of Hamlin and creates a modern supernatural story that is mostly psychological horror, but in its third act, it unleashes some bloody horror, and just enough.
The overall story and plot is rather standard and hackneyed in terms of plot points and characters that are just recycled from typical ways to make a scary movie. Acting, unfortunately, is undermined by the lack of depth in the script versus ability of the actors. Set in an orchestra, we have the narcissistic Maestro conductor, self-serving musicians fighting for the spotlight, and meeker parties wanting to have their share to shine. Outside of this, there are children because the villan needs something to hunt.
While this isn't groundbreaking, The Piper does certain elements well enough that overall I found the film to be entertaining. Most of the standard tropes are okay enough for it to be a "good" bad film. And production quality and sound design are better than the norm.
The Piper takes its time to establish it's story, building on the psychological horror and thriller elements. By the end, the film creates enough of a thriller atmosphere and third period horror to enjoy the warch. There is enough here, even with the limitations presented, that I did want to see how things were going to happen and resolve itself.