Spoilers for the ending:
I liked the reveal of whodunnit and didn’t see that coming at all, but the fact that Gracie was still alive and the only thing trapping her was a shed that didn’t even seem to be locked was a serious misstep in my opinion. I don’t get what her surviving adds to the narrative. Apart from that I liked the movie a lot. Adam Brody was excellent.
Saw a review on letterboxd where someone gave the movie 2 stars and said they saw the twist coming from 5 minutes in, which is so impossible that it made me laugh.