"Swallowing the Earth" represents output from the peculiar stage of Tezuka's career when he was foremost known as a childrens mangaka (best known for his Astro Boy) but was attempting to become a creator for adults (which eventually produced masterpieces like Buddha and Phoenix) It is not surprising that there would be some growing pains in this transition, and STE is an uneven work that fails to reconcile the very good concepts it deals with or a tone between childish and mature.
Story: 6 The story jumps all over the place from chapter to chapter, switching up characters and plot threads, but the overarching plot deals
with a conspiracy by a beautiful woman named Zephyrus to destabilize the world. Tezuka can tell excellent stories for children and adults, but this story cannot decide what it wants to be. In some chapters its a serious story dealing with issues of feminism and societal breakdown, whereas in other chapters its a childish tale about an alcoholic drinking to power himself up to beat up gangsters, complete with Loony Tunes sound effects. So while the story can be good at times, it almost feels more like a series of short stories than a continuous narrative, and loses some of its appeal. I think Tezuka could not totally throw away some of his habits from writing childrens stories, and it causes his serious attempt at drama to come off as absurd and unrealistic.
Art: 6No better or worse than any other Tezuka work (ok, worse than some of them) Hes not very ambitious with the artwork, and mostly just uses the art functionally. Also, while I would never accuse Tezuka of racism (given his own very vocal anti-racist views) but the only art that really sticks in my memory is his occasionally grotesque use of racial stereotypes. This was standard for the time, but it has aged very poorly, and its not great that its the only really memorable art from the whole manga.
Character: 4 Everyone is really two dimensional, which doesnt fit the frequently very serious tone of the work.
Enjoyment: Even though there are so many things wrong with it, its hard not to enjoy it. Its so chock full of things youd never encounter in modern manga (not surprising given its nearly 50 years old at this point) and its nice to see the deveopment of a master author between two styles. Plus its short, so it doesnt stick around long enough for its flaws to become really unbearable.
TLDR: Kind of uneven, but worth reading anyway.