From the writer of Eternal Sunshine of the Spotless Mind, and Being John Malcovich. I'd be hard pressed to explain what the movie is about. so I'll simply point to the trailer.
Necro! This is on Prime now. I just watched it. Would definitely recommend if you liked Being John Malkovich; it's got a very similar feel. Some shades of "Adaptation" as well in the play-within-a-play aspect, but I liked Synecdoche way more than I remember liking Adaptation.
I liked it, but the pacing is terrible. There are fantastic moments and absolutely stunning ideas, but the story treads water for most of the film and a lot of the individual scenes go on for far too long. I'd be afraid to recommend it to people without letting that be known up front.