Short Version: While the animation is excellent, Astro Boy is too intense for younger kids, too corny for teens and annoyingly political overall.
Screen Rant reviews Astro Boy
I went into Astro Boy with high hopes and nostalgia. I'm actually old enough to remember watching the original cartoon back when I was a kid, and being a sci-fi kind of geek even as a wee child, remember enjoying the futuristic show about a robot boy who could fly and had all kinds of cool weapons. Trailers and clips looked good so although I expected a kids' film, I was looking forward to this and brought along my 13 year old daughter and a friend of hers.
All three of us were of the same opinion: It was a waste of an hour and a half.
There will be some spoilers in this review, but as it's a movie aimed at kids, and I'm writing this review for parents, I hope you won't mind.
I swung 180 degrees in my opinion between the time the opening credits began and ended - at first the animation and dramatic music drew me in right off the bat and it looked like we might be in for something good. But then I started seeing the names of the voice actors... one well-known name after another, after another. Kristen Bell, Nicolas Cage, Samuel L. Jackson, Charlize Theron, Donald Sutherland, Nathan Lane, and more. Do I have anything against any of these actors? Not at all. So what was the problem?
More often than not when there is an animated film with a star-studded cast it's a very good indication that you're in for a very mediocre movie.
Don't ask me WHY this so - it just is (in my experience).
As Astro Boy begins we are treated to a quick animated sequence showing how humanity has ruined the planet and we cut to what could be a TV commercial for moving to Metro City - a city literally in the clouds, where everyone is happy and robots do all the work people don't want to do (including, interestingly enough "Nanny-bots"). They indicate that all is not rosy because while they float above the earth they just dump their trash and old robots over the edge to tumble down to terra firma. Oh, and people actually live on the ground, scrabbling amongst what looks like a vast garbage dump/junkyard.
The man who made this life of leisure possible via his robotic inventions is Dr. Tenma (Nicolas Cage), the father of Toby, a boy of about 13(?) who seems to be on his way to being as brilliant as his father. It seems that a meteorite fell to Earth and had at its core an energy source that could help restore the planet to its once pristine state - problem is that to do that it had to be split into "good" energy and "bad." Bill Nigh plays a scientist who of course wants to use the good blue energy to bring about, well, good. But President Stone (Donald Sutherland) wants the red energy put to use to create a super-weapon robot that he can use to go to war with the surface dwellers.
In a demonstration of the robot (where things go horribly awry) Toby is killed by the evil robot. Heck of a way to start a movie aimed at kids... Anyway, Tenma is stricken with grief, takes a strand of hair from Toby and uses its DNA and the blue energy to create Astro Boy in an effort to still have his son. While Astro Boy is 90% Toby, he is different enough that Tenma shuns him. Astro Boy ends up on the surface, and is befriended by the children living there, overseen by the apparently benign robot fanatic scientist "Ham Egg" (Nathan Lane).
Eventually Astro Boy makes it back up to Metro City to battle with a giant version of a red-energy-powered robot/President Stone and saves the day.
For younger kids (I'd say maybe 6-7 and under) the final battle is pretty intense as the giant robot tries its best to kill Astro Boy (and seemingly succeeds). Also the death scene early on is a bit much - pretty hard core for a PG movie in my opinion. Throughout the film there were (to me) many annoying references to "starting a war in order to get re-elected" and an idiotic quote by the President: "Look at history, negative energy always wins." Really? Last time I checked the Nazis lost World War II. But the topper for me was a stage set up for the President to speak at a political rally with a banner behind the podium that stated "Now is not the time for change."
Seriously? In a kids' film? I remember when movies for kids handed out moral messages, not political ones.
I did enjoy the animation in Astro Boy quite a bit, but then like I said, I'm a fan of the original character and he was portrayed well and voiced just fine by Freddie Highmore plus I'm just a fan of CGI animated films in general. There were also three goofy supporting characters that were quite funny, but I think my daughter's friend summed it up best: The best thing about the end of the movie is that it meant it was over.