As a remake of an anime series that aired in 1969, it goes without saying that Dororo would take some creative liberties when it comes to retelling such an old tale. Following the adventures of Hyakkimaru and the titular Dororo as they search for ways to reclaim the parts of Hyakkimaru's body lost to demons as an infant, the series doesn't pull punches when showing some of the more brutal aspects of life in feudal Japan.
While many aspects of the show make sense despite the fantastical setting, such as the treatment of civilians by those with power and the lengths people will go to in an effort to feel whole, Dororo isn't without its faults in many areas.
10 The Prosthetics
One of the first things viewers are treated to as the series begins is Dr. Jukai giving dead soldiers prosthetic limbs, his way of ensuring their bodies are whole when moving to the afterlife and a self imposed penance for his past actions. He also fits prosthetics to civilian victims of war who have been attacked in the crossfire, the quality of which makes them almost indistinguishable from their original limbs.
The problem with these prosthetics is that they are far too complex for the time period, moving almost as well as Edward Elric's automail from the Fullmetal Alchemist series while having no mechanical parts to speak of. Dr. Jukai explains to one boy that the limbs will move when their muscles flex naturally inside them, but that doesn't really explain how they move so well.
9 Hyakkimaru's Grip
If the basic movement of a prosthetic can be explained away as flexing muscles, Dr. Jukai has a bigger problem on his hands when it comes to Hyakkimaru's grip. Having two prosthetic arms, it would have been safe to assume that Hyakkimaru's arms were mostly for show, as their true purpose was holding the swords he uses to kill the demons who stole his body. The big problem is that he is shown many times using his hands and fingers in a way that has only recently been possible with modern prosthetic technology, during a time period when electricity was nothing more than a force of nature.
8 Hyakkimaru & The Antlion Demon
During Hyakkimaru's adventures to regain his body, he encounters the antlion demon who holds his voice. After wounding the demon, but not killing it, he regains his voice though his right foot is eaten in the process. This could have been a way for Hyakkimaru to always need Dr. Jukai, his surrogate father, to create prosthetics for him, but Hyakkimaru wasn't satisfied with that outcome.
After barely recovering, he dives back into the antlion pit to kill the demon once and for all, which, for some reason, makes his eaten leg grow back to normal. This could be explained as the demon trading his voice for a foot, but considering Hyakkimaru's body was taken in a ritual sacrifice and not simply eaten, it starts to poke some holes in the story.
7 Dororo's Map
About halfway through the series, Dororo is revealed to have been tattooed while she was younger with a map of riches hidden by her father. This tattoo, for some reason, only appears on her back when she is particularly warm, such as around a fire, though the one on her mother's back doesn't have the same treatment. The mechanics of how such a tattoo would be done on a child aside, a flashback shows that she was asleep at the time and had no knowledge of it until someone else told her it was there. As a general rule, tattoos involve many sharp needles and a fair bit of pain, so it seems highly unlikely that she wouldn't have known what her father was doing even if she was asleep.
6 Biwamaru's Vision
As Hyakkimaru is sent down the river to save him from death as a newborn, a man looks on at him floating away with his not-Byakugan eyes, taking note of his unusual aura. While he appears to have the same visual powers as Hyakkimaru in the future, unlike the boy devoured by demons, the priest walks with the assistance of a cane to help navigate the world, something Hyakkimaru apparently never needed despite the fact he can only see living things. His reliance on the cane is never explained, which makes it more nonsensical when he discards it entirely to fight off demons multiple times in the series.
5 Hyakkimaru's "Evil" Aura
The main reason the priest returns many times over the series is to keep an eye on Hyakkimaru, as his aura is turning the same red color as the demons he kills, with it increasing with every kill. Though the priest states that this color change most likely started when he killed a group of soldiers who killed civilians he was staying with, if that were really the case, there would be a lot more red aura in the world. As there are samurai and bandits in nearly every town Dororo and Hyakkimaru visit, many of which have taken lives with more reckless disregard than Hyakkimaru ever has, there is no reason why Hyakkimaru should be any different from those men.
4 The Spine Regrowth
At the beginning of the series, it isn't entirely clear which body parts had been taken by the demons in their pact with Daigo, as the infant Hyakkimaru was left with his basic skeletal structure, muscles, and internal organs. One missing piece of his body which raises more than a few questions is his spinal column.
During episode 15, Hyakkimaru kills a moth-like demon who has been feeding on children, which ejects a makeshift spine from his body made by Jukai and it is replaced with his real one. Considering how important a spine is to movement and general growth, it is one of the few body parts that he probably couldn't have lived without even with the goddess' protection.
3 Episode 15
Speaking of episode 15, there is one glaring aspect to that episode that makes no sense compared to every other episode in the series: the animation quality. There are times throughout the series when the quality dips slightly, possibly in homage to the original series which would be incredibly dated by today's standards, but the sheer lack of quality in this episode puts even Dragon Ball Super's infamous Goku vs Beerus fight scene to shame. What makes it more glaring is that there was no gradual dip in quality over the episodes that came before it, and it looks like the production company ran out of time for just one episode.
2 Hyakkimaru's Survival
Hyakkimaru may have been saved from a fate worse than death with the sacrifice of the goddess statue, but that alone doesn't explain how he was able to survive being torn apart as an infant. While many people have been able to live without their senses or limbs, the fact that Hyakkimaru was able to survive without any skin is reason enough to not believe his survival should have been possible, even without divine intervention. Even putting this aside, the fact he was able to fight unaided against multiple demons with the bare minimum level of eyesight, when trained soldiers were being killed left and right by the same creatures, is entirely unbelievable.
1 The Show's Title
In context, the show being named after a seemingly secondary character makes sense. During its initial manga run, Osamu Tezuka, the creator of not only Dororo, but also the likes of Kimba the White Lion and Astro Boy, intended for the series to follow Dororo through more adventures after her journey with Hyakkimaru. This wouldn't be the case, as the manga was canceled after two years and concluded with Hyakkimaru's storyline being completed. As there have been other versions of the story told under different titles, including a 2004 PS2 game titled Blood Will Tell, it's not outside the realm of possibility that the remade anime could have used a different title as well.