Justin JM (kind of inactive, kind of not)’s review published on Letterboxd:
It's the reverse Life is Beautiful, where in that film that first half was a bit so-so and the second half exceeding all the faults of the first.
Room is a movie with two halves; one half I consider a god damn masterpiece and the other, not so much. The second half has its moments, there's the dynamics of the first half that are present, but it's nowhere near as good as the first half was, which was a brilliant work of art.
It had tension, a sense of wonder but surprisingly no claustrophobia, compelling characters, and mystery to it.
The movie is told through the child's point of view, who has lived in such a confined room his entire life, only to be taken care of by his mother and an occasional mysterious visitor. The world of Room is expansive, at least according to the child's eyes; he has created a world that was created by his mother that she created to keep her son creative and keep boredom at bay.
Now the movie really relies on these two characters, how well they're performed and written is mandatory for this movie to be at least somewhat interesting. Thanks to Larson's and Tremblay's performances and amazing acting skills, they exceeded excellently and made for compelling characters. Their dialogue was rich and kept me invested, the way they lived and used their time kept me fascinated, and the way they relied on each other as family kept me rooting for them the whole way through.
That is until the second half of the film. The second half does have its moments, some of the moments that are better than the first half, but the ones that don't make it a bit of a drag. Some scenes in it peaked my interest, some scenes made me cry, but a lot of the scenes held my interest with a weak thread from my interest of the first.
I might be sounding a bit harsh on this part of the film, but it's only because it deserves a comparison to the second (and to avoid spoiling). The second half is still worth watching, so I don't recommend turning off the movie as soon as the first half is complete, but I think we can all agree it is nowhere near on the level of the first half.