Basically all that you need to know is that its better than the first but worse than the second plus the irish accents were terrible for the large majority of the 1666 time period. All though it doe finish off the story well, the one-dimensional bad guy was really annoying and a disappointment as they didn't really have any good purpose for continuing the bloody massacre other than greed. I wish they had a legitimate reason for being evil instead of pulling the greed card, it just ruins his character and makes the whole series feel less serious and less cool.
Review of Fear Street: Part Three - 1666
