They never explore the sheer horror and tragedy of Astro Boy as much as they should.
Imagine you're a child. Your life seems normal, albeit your father is a bit neglectful because he's absorbed in his work. One day, your father suddenly becomes incredibly attached to you. He takes leave from work, he starts homeschooling you. He wants to spend all of his time with you. But it only lasts a week. Maybe a month at best. He becomes cold again. You're not his real child, he complains. Just a pale imitation.
You find out then that you died. You were hit by a car and your body was mangled. But you're still here? No, you're not. You're a robot. But you remember being human. You know you were human. You remember growing up.
The memories are fake. The real you is dead and gone and your father, this stranger, built you in a mad attempt to bring his child back. He doesn't love you. In fact, he despises you. Just looking at you makes him want to puke. But Dad, I love you, you say. He screams at you to leave. You're not my child.
He wants nothing to do with you. He sells you to a robot circus, where they're tortured and electrocuted into obedience. You can feel all of that pain. You were programmed to feel pain and emotions, just like a human. Every night when you try to sleep, you feel a pain in your chest where your heart used to be. Do you even have a soul now? You've lost everything and it wasn't even your fault.