• • Flat female characters : the deuteragonist, Maika, falls in love with Ash due to a change in his smile. There's nothing major. It just happens. She's goes from hating Ash to becoming his #1 supporter in a couple chapters. Unfortunately, this makes her an extremely flat character as her main function is to act as comedic relief and as a foil to Ash's "genius". What's even worse is that Maika isn't the only female character to be relegated to such a role. In fact, it feels like all other female characters introduced are there to highlight and emphasize Ash's "genius".

• • Inconsistencies in Ash's knowledge : Ash's past and reincarnation is a side-note in this series, but it serves as justification for his advanced ability to read and interpret knowledge from the Ancient Civilization. However, the breath and depth of his knowledge can be extremely jarring at times. Take the following example for instance. Although, possessing knowledge of beekeeping and bee products like honey, it seems unreasonable for Ash to not know about beeswax. This is especially so, when Ash has created many other products such as aloe-based cosmetics and medicine and has claimed to avid reader in his past life, possessing knowledge about biology, chemistry, metallurgy, etc.

• • Really slow world building and technological plot holes : In this world, an Ancient Civilization with modern technologically once existed, but it just collapsed one day. We don't know how, but Ash theorizes about this over the course of the series. As a result of the collapsed Ancient Civilization, there are a lot of anachronisms in this world's technology. We have books containing knowledge about aircrafts, but people still don't practice good hygiene, have soap, or do not know about fertilizer but do know about practicing crop rotations. A lot of this knowledge is locked behind the books from the Ancient Civilization, and only knowledge passed down orally is put into practice outside of the stuff that has been deciphered. Which leads to this series biggest plot-hole, if these books contain the knowledge necessary to revolutionize the world, then why Ash? There is obviously enough motivation and reason to read and interpret these books, and clearly there are plenty of literate people in his world if governments and organizations like the Church exist. Are you telling me that no one could understand them for, no joke, centuries until Ash came along?

As said by others, the other characters are very flat. For example, the female lead mostly just blushes and heaps praise in the MC. It's grating that people make 180 character changes as well. For example, the MC's father is a horrible drunk but stops overnight and becomesa decent person.

The bit that annoys me the most: Fairly early on in the story, the village children go into the forest to gather herbs and the main character mysteriously falls unconscious and has to survive in the wilderness alone. Somehow the MC deludes himself into thinking that he tripped without suspecting at all the other boys in the village who were behind him and very obviously hate him. Moreover, you'd think that on getting back to the village and hearing that they told everyone he was attacked by a boar this supposedly smart MC would notice, but nope! The volume ends without any kind of discovery or justice. Moreover, one of the boys that we know was involved in the event, who tries to attack the MC again later btw, suddenly makes a character 180 as well. The MC even fixes this boy's family relationship and gets him a job. The hell.