Connor Carey’s review published on Letterboxd:
While "Fear Street Part Three: 1666" is probably my least favorite of the trilogy, it's still a solid conclusion to this story that for the most part sticks the landing. I wasn't sure what exactly to make of it at the start and was honestly a bit worried. Seeing the same cast in different roles and their heavy accents was pretty distracting at first but thankfully it doesn't take long to adjust to and after the first 20 minutes, it picks up quite a bit. I really love this cast too with the performances of both Kiana Madeira and Olivia Welch being particularly strong here. While I still wouldn't call these films necessarily scary this one definitely creeped me out the most and it's definitely the darkest and most disturbing by far. Sadly though the flaws in this one stick out way more than the others and it's a bit messier overall. I understand they had to structure this the way they did but there's no denying that it feels like two different movies with completely different paces and tones. While I might not be as high on this one as its predecessors (I was pretty tired when I watched this so maybe it was my mood), I still think this was a solid conclusion with a good twist and for the most part has a satisfying payoff.