All Animation Is Disney: Thanks to his Disney-inspired look, Astro is occasionally mistaken for a Disney or otherwise western cartoon.
Astro Boy (manga)
Germans Love David Hasselhoff: Australians make up a large fanbase, partly due to being one of the few countries outside Japan that got the 1982 series.
Genius Bonus: The goofy looking planes piloted by the Hot Dog Corps in the first volume of the collected edition may look like something made up for a sci-fi cartoon, but they're actually a real design, specifically the Convair Pogo, a very early prototype VTOL fighter.
What Do You Mean, It's for Kids?: There's a story arc about a group who skins dogs and turns them into cyborgs. While it's not actually shown on-panel, it's still incredibly dark. Likewise, other stories explore topics like racism (through anti-robot prejudice), war, and child abuse (as in Astro's origin). Nevertheless, it's still aimed at children. Likely because Tezuka respected his audience and didn't want to talk down to them.
Astro Boy (1963 TV series)
Woolseyism: The original title theme was instrumental. When NBC dubbed the show for their English audience, lyrics were added, sung by a children's chorus.
Complete Monster: President Stone is a man whose apparent stupidity and childishness truthfully mask a murderous and ambitious personality. Stone alienates, withholds resources for, and threatens war against the downtrodden surface-dwellers out of an insane belief it will assure his reelection, and commissions scientists Tenma and Elefun to develop the powerful Peacekeeper robot to better serve in his useless war. When his own carelessness and power lust result in the death of Tenma's son, Stone shrugs it off and continues to force Tenma and Elefun's compliance under threat of execution. After Tenma rebuilds his son as a robot named "Astro", Stone endangers countless people to capture the boy, mocks him over his lack of true humanity, and tries to rip out of his power core to power the Peacekeeper. Upon merging with and assuming control of the Peacekeeper, Stone begins destroying the city and threatens to crush Astro's numerous friends to death to draw him out and kill him, focused solely on finalizing his plans to lay waste to the surface-dwellers and continue his rule as president.
Toby's death; he sneaks in to see the Peacekeeper demonstration and decides that getting closer is a good idea. Then his father activates a defensive barrier when the robot goes rogue, but Toby gets trapped behind the barrier. He starts calling for help, and Tenma desperately tries to override the barrier. He fails, and can only spend a few minutes reassuring Toby as the robot tries to vaporize the barrier. The barrier stands, but Toby doesn't. When Elefun successfully deactivate the robot, Tenma can only find Toby's hat.
Hamegg Tasering Astro several times, first to knock him out and put him in the ring, and the second to make him fight Zog. It hits home that Astro may be a Nigh-Invulnerable robot, but he's also mentally a child and Hamegg thinks he's justified because Astro isn't human.
Older Than They Think: Quite a few people claimed that giving Astro butt lasers was disrespectful to the source material and Astro's creator... Despite the fact that he had them in the original work.