For the first half, I was enjoying the ride but sort of wondering how such a flimsy premise (a movie about a writer not having any ideas for his movie) made it to screen. Then, Charlie and his brother have a revelation, and from that point it's a serious nailbiter.
If you're a Being John Malkovich fan, you'll be happy to see John Malkoviches roaming the set and cameos by John Cusack and Catherine Keener. You will also see other stars I know nothing about, such as Meryl Streep.
This is a sucky review, but I don't know anything about films.
Oh, and if you know Lobster, you'll be amused to see his namesake figuring so heavily into the plot.