A missed opportunity for a better movie. The movie seems good... if you don't know the real story... which is more suspenseful, intricated, and deep. They reduced it to "the killer nurse and the hero nurse" with a predictable ending. In real life, there were a lot more heroes: the 2 investigators don't get as much credit as they should since they did half the things that this movie attributes to the "good nurse".
The real victims that helped resolve the mystery were replaced by other characters. Why did they replace the priest? His exhumation and autopsy provided the answers. The son of a lady murdered in the 90s who raised a red flag but was ignored... he deserved a few minutes in this movie.
And at the end, when he's asked why he did it, he answers "because they didn't stop me" and everything stops as to give him a way to rationalize what he did, like that's the sole reason for his actions. Yes, many hospitals didn't stop him and were criminal, but that doesn't make him innocent or another victim. He chose to murder 100s, he's no victim of the system.
Again... the real-life story was written for them already and they decided to reduce it to something simple, they eliminated characters and key steps in the investigation.
Waste of time. Read Wikipedia for the real story.