Movieman630’s review published on Letterboxd:
Fear Street: 1666 is a very solid and satisfying, if not quite spectacular, ending to the Fear Street trilogy. It is probably the strongest film of the series, but that's mostly due to the fantastic fist half of the film. In this part, the film really shines, reusing actors to tell a great and interesting historical story. The film is able to effectively touch on ideas of sexism and homophobia during its historical tale. There are some wonderful twists that have strong implications for the entire series.
However, the second half of this film doesn't really do anything new. Though it is still fun, it's mostly just the same things we've seen two other times by now. It is cool how well it is able to tie together all of the dangling plot threads of the previous films, but it never gets all that tense.
Overall, 1666 is a much better wrapup to the other films than it is a film in its own right. That said, it is a third film in a trilogy, so that is enough. Plus, the first half of the film is some of the best stuff of the whole trilogy.