Ajin ends up being something you force yourself to watch just to see messed up ways to kill or torture someone. It tried to pass as deep by showing the effects of becoming desensitized because of immortality, and how humanity becomes terrified of such creatures living amongst them. All that were just dressing, it didn’t explore the themes on the level of Parasyte and ended up being excuses for gore and murder.
It was tortureporn for edgelords instead of a decent story one can enjoy, and even then it doesn’t hold a candle next to something like Tokyo Ghoul, (only the first season, obviously). Everything else is tensionless battles between Ajin who cannot die, using eye cancer CGI. And yes, it is crappy and the reason why almost nobody bothered to watch it. It was so overlooked in the community they didn’t even nominate it in the Crunchyroll awards of 2016, despite having one of the best villains of the year.
Those who defended it by claiming the CGI is what made it stand out, shot themselves in the foot since it was standing out so much to the point nobody liked it. The previous work from the same animation studio was Knights of Sidonia, which although equally schlocky was at least not using the terrible CGI in an off-putting way. It was not out of place since a setting of genetic engineering in the far future was excusing the eerie and artificial way everything looked much better. Ajin takes place in a mundane Japan of today, so it’s bizarre to have robotic characters and low frame animation for no thematic reason and thus it makes sense why nobody liked it. Frankly, the only thing that benefited from the CGI was the appearance of the black smoke monsters, which look really cool as Stand knock-offs from Jojo’s Bizarre Adventure.
Believe it or not, the anime has more problems than the animation, and that is the retarded protagonist. Most deaths and torture scenes wouldn’t happen if he had a 3 digit IQ. Nothing he did made any sense, such as not hiding his face in public areas and avoiding the constant attacks of people who recognized him. He was passive, needlessly overcomplicated every situation, did nothing useful most of the time, and constantly made the plot to go in circles thus becoming detrimental to the narrative. Nobody likes such characters.
Satou, the main villain, was the best thing about the show, since he was the exact opposite of that idiotic MC. Proactive, had an agenda, and was experienced in battle. In effect, he was the story of Ajin. If he was the main character, or at least if he had found Kei much sooner, the show wouldn’t be so off-putting. But no, we couldn’t have good things and even Satou got ruined when that moronic MC defeated him because the plot said so. A complete travesty from top to bottom.