TLDR: It's the adaptation of the book that I'd hoped to see. Here are my 2021 thoughts on the book.
Today was the first time I've set foot in a movie theater since 2021 (well I at least tried, once, in 2023; see jaundiced thoughts here), and it was an hour and a half drive each way to get there. Worth every minute of the trip. Go see it in a good quality theater while it's still in its original run, then buy the blu-ray next Christmas.
So... 4.5 out of 5 stars? Maybe 5, I'll have to see it a few more times before granting that high honor. It's good though, so go see it in a theater while you can. It looks great up on the big screen, plus we need to vote with our dollars when given something to bother voting for. Lord knows, that's a rare enough occurrence these days.
Yeah, yeah, the puppet alien stuff is good, as good as all the critics are saying. However, don't fall into the cutesy-alien sentimental trap here. Look at the person behind the carapace, at the fully developed character. It took competent writing, scriptwriting, puppeteering, and voice acting to let Rocky's personality show through. Don't waste all that effort treating this as another cheap Spielberg ET exercise in emotional manipulation, because it isn't. This is a reasonably complex character, and while the kids can get a thrill from seeing an articulated rock pile, adults can appreciate what's going on too.
Finally, it's a miracle this story made it through production hell. In a spoilerific interview here (No, don't click if you haven't read or seen it! Really, don't!), the scriptwriter reveals how he was gently pressured to take out one key plot twist. If the studio execs had succeeded in so gutting the story, my review would have been reduced to 2 out of 5 stars: "Nice special effects, but it's a shame they threw away the book. Don't bother." But they didn't! So go see the movie.
This is not to say that major parts weren't adapted for screen. And that's OK. Not every technical in-joke or plot complication can make it – or even translates – to film. The main point though is, the core of the story is there, it is a good story that people who've read the book will recognize, and it was faithfully translated to screen. Again, this is the adaptation of the book that I'd hoped to see.