I thought this movie was absolutely terrific. It was fun, interesting, and refreshing, and any doubts or qualms I had with it in the beginning were resolved by the end.
In fact, a little ways into it I thought I had guessed then ending, and thought "wow, what a neat little concept." By the end, it had taken what I thought would happen and added a few twists, and really left me pleasantly surprised. I've seen plot progression similar to this before, but this really stuck the landing and left me wanting more (in a good way).
Some of the performances and character decisions do feel a little off in the beginning, but this makes sense at a certain point and becomes part of the charm.
As a directorial debut and possibly best performance yet by the rising Joe Keery, I have to go with a 10/10 for this one. I can't think of anything that would have enhanced it, and it all wrapped up in a satisfying, if not 100% original, way.
By the way, I only knew about this film because I follow Justin Long (apparently a friend of the director) on Instagram. Really curious as to how this gem slipped by with minimal promotion or recognition.