Patrick Jensen’s review published on Letterboxd:
I have had this film on my watchlist for a very long time. The reason for that is that I think Charlie Kaufman is one of the most interesting screenwriters in the film industry, even though his style is easy to parody, as seen in Community, in the episode where Abed tries to create the ultimate meta-film. Among the films he has written that I like are Eternal Sunshine of the Spotless Mind, Being John Malkovich and my personal favorite of his, Adaptation. Synecdoche, New York is Kaufman's directorial debut, and if you ask me, it is probably the best film he has been involved with so far.
The film is about Caden Cotard (named after Cotard's syndrome, where one holds the delusion that he/she is dead, either figuratively or literally), a theatre director who receives a MacArthur Fellowship, which makes it possible for him to create his masterpiece. During the process of creating this play, the lines between reality and fiction are blurred, and time gets distorted in his mind. The comparisons to Federico Fellini's 8½ are easy to make, as they do share many similarities, but where 8½ did have a clear distinction between dreams and reality, this is not the case with Synecdoche, New York. Here, dreams and reality are fused into each other, thus creating a hyperreal world, where time passes on a completely different pace, and this rapid progression of time then functions as a synecdoche of Caden Cotard's delusions. This structure of the film is part of what makes it such a fantastic film in my opinion, as we not only experience what Cotard is going through, but we also see it in the way he would perceive it. Visual storytelling at its best.
But it is not just the plot and the structure that is excellent here. The performances are also fantastic, with Philip Seymour Hoffmann delivering one of his best performances as the delusional Caden Cotard, whose life never turns out the way he wants, and who constantly makes his personal life a bit of a living hell. Catherine Keener, Michelle Williams, and Jennifer Jason Leigh also deliver great performances as the women involved in Caden's life, but the standout performance comes from Samantha Morton as Hazel, probably the most important woman of his life. Her emotional support and romantic feelings for Caden are conveyed expertly through her acting, and even her irrational decisions such as buying a house on fire are made understandable. It is a character who could easily have been written and played in an over-the-top manner, but Morton handles the role with subtlety and enough sympathy to make her stand out among a crowd of great actors.
While I can't say that I can explain everything that occurs in this film, I can say that the plot, writing, structure, acting and directing of this film creates a fantastic unity, which I can only admire. While it might not be a film that will appeal to everyone, it is definitely a unique film that I can say that you have to watch, as it is a brilliant piece of filmmaking.