Raster Image’s review published on Letterboxd:
A film of two halves: in Room, and out of it. All with the point of view of 5 year old Jack (Tremblay). I actually saw the first half at a film festival 5 years ago, and then the projector broke down. I thought it was quite good but not so good that seeing the rest of it was a matter of urgency.
In the first part we get to imagine what it would be like to live and grow up in a single room (Jack), or to be held captive from age 17 and have to bring up a child on your own (Jack's mother Joy, played by Larson). Both prisoners are believably pallid from a life indoors. It's convincing and touching, and the way it's shot gives us the feel of living in a whole world that's just a few metres across, no hint of any other world apart from the occasional leaf on the skylight or inquisitive mouse. Their captor pops in for a quick bit of rape sometimes, he is played by Sean Bridgers as a regular guy who happens to be misogynistic, determined, and practical enough to keep them locked up for such a long time—banal evil.
The second half gives us a sensitive portrayal of Jack adjusting to the outside world, and Joy working through her post-trauma. Inevitably, it's not as interesting as the first half, but there's plenty of good acting.
And then of course there's the transition—the escape—which is proper suspenseful. And moving when, against the odds, it comes off. We really worry about the many ways it could go wrong, which is a testament to how the actors have drawn us in.
Music is subtle and effective without being great, and avoids getting too soppy until near the end. The most interesting thing it does is sound like the soundtrack to some idyllic misty-eyed coming-of-age nostalgia piece during the growing up in Room section, a nice contradiction.