This movie is a) not what it seems and b) brilliant

Rating: 10/10 (9 February 2016)

The Coens sometimes release movies that are immediately accessible, where everything you see is more or less all that there is to take away from it. True Grit, Fargo, Raising Arizona, Blood Simple, Miller's Crossing, etc.
Hail, Caesar! isn't one of these immediately rewarding movies. It's one of the other kinds of movies they release where repeated viewings and some contemplation is involved because not all of what's going on is immediately accessible on your first exposure. There are multiple layers of interpretation at work simultaneously, making for a lot of meta- content. More like a puzzle that rings around in your brain long after you've seen it. Barton Fink, The Man Who Wasn't There, A Serious Man, etc.
Immediately after my first viewing, I was in the same boat with a lot of the reviews here, where I was convinced this is a Coen dud. Everything seemed to ramble around with no real connecting story to carry it through. My first reaction was: 'this sucks'. My complaint was that none of the on-screen action seemed very well connected at all to anything else. The trailer kind of created an impression of a comedic kidnapping thriller with some Hollywood tributes thrown in for candy, but that isn't the experience you get at all.
Instead I was left asking: why is so much time spent on the different movie-in-movie sequences? What does any of it have to do with the main character's story, except tangentially through his work for the studio? It just seemed like kind of a pointless pastiche of pseudo-tribute scenes with maybe some funny lines and Hollywood observations here and there.
But, these guys have been making movies forever. They don't just throw sh*t in for the hell of it and cross their fingers. Every scene and character has a function, and it's always related back to a central idea or theme.
Think of the Mike Yanagita character in Fargo - the weird scene where Marge goes to visit him in the restaurant and he goes all stalker-creepy on her and makes up a story about his dead wife. I puzzled over that scene long after seeing it the first time. But, of course, that scene and that character has a meaningful, significant function in the movie. Google 'what significance does mike yanagita have in fargo' if you're fuzzy on the details.
So, what's the unifying idea in "Hail, Caesar!"? What is this thing about? My view is that this movie is exploring one central question: "do our actions in life matter?". Every story element is coming at that question, either seeking an answer, or trying to provide one: Mannix, the communists, religion, and movie makers.
To see this in action, and without including any spoilers, wipe your mind clear of previous judgments and opinions, and watch it again with fresh eyes and these questions in mind:
1. What problems is Mannix asked to fix?
2. Does he take 'direct action' to fix those problems?
3. What contribution does his action make to the solution (if there is one)?
4. Would the problem have 'solved itself' without his action?
5. Bonus question: why are Thora and Thessaly twins?
...if you watch this film and look for evidence of this central question, you will find it in every single scene. Every single character and line is contributing to the exploration of this question and the different answers. Watching the movie through this lens, I had a completely different experience, and found myself loving every minute of it. These riddles and rhymes are everywhere in the movie.
Do the Coen's try to answer the central question in the movie? Yes, they do.
Their answer is: 'were that it were so simple'
Or, said another way: 'it's complicated'