Solo is a very good sci-fi skiffy fantasy wild west space opera movie.
No-one who grew up playing with toy space ships can fail to enjoy the big middle section in which a space ship bounces around a gravity well while almost being eaten by a giant space octopus while trying to rewire the dead robot's brain into the computer while trying to feed Plot Devisium into the Warp Drive while being chased by TIE fighters and Star Destroyers.
My mind is still slightly blown by the fact that I have lived to see this sort of old school Lensemen pulpery projected onto big huge screens in shopping centres and other people apart from me evidently want to watch it. (Outside the cinema in Bristol there is a giant video screen advertising a movie about a dog show and lady's shaving razors like in Blade Runner. I could have ordered noodles if I'd wanted to. Just saying.)
Solo gets the visuals and tone and texture of Star Wars exactly right. It does this by a process of themes-and-variations: Han starts out working for a gangster who is quite obviously Jabba the Hutt without actually being Jabba the Hutt; and ends up on a desert planet full of picture postcard views that look almost exactly like Tatooine without actually being Tatooine. And there are three separate photocopies of The Cantina. I think maybe "sleazy Mexican bar full of aliens" is simply a Space Opera Trope of which the The Cantina is merely a particularly memorable example.
It's a big universe and probably there should be planets that look like Milton Keynes on a wet Friday afternoon and planets populated by sentient rocks and super-intelligent shades of the colour blue. But there is a kind of consensus about what Star Wars should look like and Solo looked like that.
Of course it is ridiculous for anyone other than Harrison Ford to be Han Solo. It was ridiculous for anyone other than Sean Connery to be James Bond, until it wasn't; and ridiculous for anyone other than William Hartnell to be Doctor Who, until it wasn't. I don't know if I quite believed that the young lad who knocks about the universe getting in and out of scrapes is the same person as veteran smuggler who Luke bumps into in the second act of A New Hope. But he was an enraging enough hero for this kind of space opera. There is no doubt that much of Han Solo's charm came from Harrison Ford, not from the script. ("You can type this shit, George...") Perry King speaks many of the same lines in the Radio adaptation, and he comes across as a rather more mono-dimensional unsympathetic mercenary. But Han Solo isn't reducible to Ford. For every minute of screen time, there are ummpety-ump pages of printed text and umpety-ump comic book panels, all telling the Further Adventures of a figure who is identifiably Han Solo, none of which have any input from Harrison Ford.
It is Leia who called Han a mercenary and she wasn't being quite fair. Han wanted the reward money to pay off Jabba the Hutt, because if he doesn't, Jabba the Hutt will murder him. We never see any sign of him enjoying the trappings of wealth or wanting an indulgent life-style. That's followed through mostly in Solo. Han keeps having to do heists because he owes money to various galactic undesirables, but this isn't quite the life he would have chosen.
The "how Han first met Chewie" seen is funny, clever and retrospectively a bit obvious.
The Han Solo who we meet on Tatooine is older than Luke, a veteran, maybe 35 to Luke's 19 if we go by actor's ages. He obviously has a history, and the kinds of stuff he does in Solo is definitely the kind of stuff we would have imagined him doing. He gets involved in impossible heists, strikes arrogant poses in seedy space bars, falls out with nasty gangsters, is betrayed and counter-betrayed multiple times but usually turns out to have been one step ahead of them. I didn't believe in the Prequels because I didn't believe that the kind of adventures Ewan McGregor was having were the kinds of adventures that Alec Guinness would have had when he was young. Alden Ehrenreich has exactly the kinds of adventures that a young Harrison Ford ought to have had.
One of the cool things about a charming, veteran space pirate is that there is a history and a back story which he knows and you don't; and one of the specifically cool things about Han is that he keeps giving us tantalizing glimpses of his past. Arguably, we don't want to see Han playing cards with Lando, any more than we want to see Ben Kenobi and Luke's Mysterious Father fighting in the Clone Wars. But that is an argument against prequels in general, not a criticism of this film in particular.
It is interesting, is it not, how things that we all assumed were canon but have never actually been mentioned before slide into these movies and no-one bats an eyelid. I absolutely knew that the game on which Lando wagered the Millennium Falcon was called "sabac" but I am pretty sure I learned that from the RPG, not any movie.
Star Wars is a collision between three things. Star Wars is actually a collision between a lot more than three things, but three will do. It's first and foremost great big clashes of dreadnoughts and doughty little dog-fighters; a space ships and aliens space opera yarn. Star, in a very real sense, wars. But in the middle of the big star war there's a King Arthur fairy tale about the last quest of a magic Knight with a glowy sword. And somehow about two thirds of it takes place in a world of frontier towns, cactuses, and dodgy bars; space pirates and space gangsters. Space opera plus space fantasy plus space cowboys.
The main movies have increasingly focussed on the Jedi Knights to the exclusion of everything else; Rogue One was basically the Space Wars bit with everything else taken out. Solo is a space cowboy story with no Jedi at all. (Spoiler alert: Well, hardly any.) And what it proves is that the cowboys in space element was always what Star Wars was mostly about: if you had to define the saga in two words, "Space Western" does the job much better than "Science Fantasy." There are no casinos, coffee lounges, libraries, or idyllic romantic interludes in Solo: no moment at which I thought "I am sorry, but this is just not Star Wars."
But neither is there anything surprising or imaginative in the movie. There are good plot twists, but they are the kinds of good plot twists that you would expect in a movie of this kind; the kind of plot twists that anyone who had seen Empire Strikes Back would see coming at a distance of less than twelve parsecs. This is the kind of Han Solo movie you would have made if you had been asked to make a Han Solo movie. This is the kind of Star Wars adventure you would have made up when you were running the Star Wars RPG, and indeed did. Two thirds of the movie consists of a motley crew of mismatched individuals who get on okay, but quarrel a bit, in a spaceship that they kind of call home; which makes it feel not entirely unlike an episode of Star Wars: Rebels. Indeed, the ending, not quite a cliff hanger but with distinct loose ends left untied, felt very like the end of a TV pilot episode. I suppose that since everyone decided in advance that the film was not a success, we won't now get to see the follow up.
To an extent, any Star Wars film maker is damned if he does and damned if he doesn't. Do something experimental and different, use a Star Wars episode to say something about the Star Wars mythos, give us surprising takes on much-loved characters and fans (not all fans) will accuse you of violating the Sacred Saga. Fly close to the genre; do the kinds of things we expected and hoped you would do; show us the stuff we always wanted to see and fans (not all fans) will accuse you of making a redundant film that no-one asked for.
There is a very minor sub-plot about a robot. Some people have seen ten Star Wars movies and two TV shows but are still surprised that Star Wars movies often involve cute comic relief. The robot thinks of itself as female, and is very cross that robots are being used as slave labour on that planet that C3PO is concerned about being sent to the spice mines of. (Chewbacca is not wild about what they are doing to the wookies there, either.)
Some people think that this is an unwarranted intrusion of politics into what is basically just a series of adventure movies about plucky revolutionaries overthrowing a fascist regime. If you are one of these people, you need to seek professional help immediately.