We made it about 20 minutes before my 5 yr old son asked to leave. He was into it in the beginning - seeing all the robots. The closest thing he has ever watched to this are the transformer cartoons. (the old ones) But when things got sinister, he got uneasy. And then when Astro boy 'disappeared', (thankfully, we don't see a lifeless body) my son asked if we could go home. When he asked again after the robot boy at home scenes with the distressed father, we left.
Not for little kids. The grown ups are too sinister, and the little boy getting killed by the bad robot is too much.