Once you figure out what's going on, the story itself after the fact isn't exactly groundbreaking. However, the way they pull it off is pretty impressive. I don't think people consider enough the degree of coordination that's required to apply pacing and tone in any given film, especially when you throw in special effects and lighting potentially dependent on time of day. This movie does all of it pretty flawlessly, and creates an almost tactile momentum that carries you through. While I wasn't surprised it ended when it did, not once was I looking for it or had it in mind until it was over. That's usually a clear mark of competence for storytelling. The final scene did feel a bit empty, though, for reasons I can't quite explain. Maybe a clearer angle of a final, knowing look from Celeste would have remedied this, but that's just a stray thought, not genuine criticism.
Acting was spot on for everyone involved. Dylan O'Brien is something of a standout. I've seen his work before but this one really let him shine. Lauren Ambrose also completely sells the manic/distressed persona and just became this person. Eliza Scanlen not once failed to sell me what was happening on-screen. Talents like these make it so much easier to lose yourself in whatever is being shown and it's always appreciated.
Great watch. Adept filmmakers on display and I'm here for it.
