Jacob Gehman’s review published on Letterboxd:
Room is conceptually better than its execution. The execution itself is fine enough, but seems too limited. It's a movie that is better (even in its limited way) than I could appreciate as a viewer.
A mother and her son live in a small room, just big enough to fit a bed, a wardrobe, a small kitchenette, and a toilet/bath. Jack, the son, has never been outside of the room.
At the outset we're not sure why. Why are they always in Room? Is it a post-nuclear war shelter? Did society crumble and it's a Wild West out there? Are they prisoners? Questions swirl, but even as we only get faint inklings of the force keeping them in Room, we see the philosophical what-ifs that Room plays with.
What if... you were born in an enclosed area and your only concept of the world was the room?
What if... you could get out of the room? What would it be like seeing the world for the first time?
How would you respond to people? How would you respond to things? How would you be able to filter out all of the background chaos?
It's through the eyes of 5-year-old Jack that Room paints his entombed existence and it's through his eyes that we escape the room and see the world. Just on concept, this is a pretty satisfying undertaking.
The muddled narrative flips back and forth between Jack's perspective and that of an impartial 3rd party. Especially after most of the first half of Room is spent literally in a room, mostly seen from Jack's perspective, the second half's step back feels a bit ill advised. While the above questions are explored, we find out the answers (at least, as they apply to this specific narrative) in a way that feels downright clinical. In movies like this you can either have us experience the questions and answers, or you can tell us the questions and answers. Room leans too strongly on the latter, especially during that second half.
This isn't a complete value killer. Even at arm's reach the narrative is compelling enough to drive two hours. The performances are solid all the way around, and great from Brie Larson and Jacob Tremblay. And while the questions/answers could have been answered better, it's still notable that they're addressed at all.