Few things are more painful than seeing a beloved manga in anime form, only to discover the show fails to do the source material justice. It's also annoying to invest time in a bad or mediocre anime, then find out it was an excellent manga, but the full story spans hundreds of chapters. While good adaptations don't have to mirror their manga counterparts, they should retain the manga's merits and provide a coherent, enjoyable story.
Let's take a look at several of the worst manga adaptations ever made. Some, like My Little Monster, present romantic entanglements and vague hints at a backstory without a true resolution. Others, like Tokyo Ghoul √A, veer onto a different storyline, disregarding any of the elements making the manga great.
The anime version of Tokyo Ghoul √A makes a bold choice, and many fans aren't happy about it. Instead of having Ken Kaneki continue to fight against Aogiri Tree as he does in the manga, the anime has him join them.
These major changes have interesting potential if executed well, but it's a risky decision the Tokyo Ghoul √A anime fails to warrant. Several plot points are completely nonsensical, resulting in a dramatic change in the tone of the series.
Unlike the first season where they took deep dives into the characters' minds, the anime's creators focused on random action sequences, which may occasionally seem senseless without knowing the drives behind them.
Berserk is a complex manga series taking readers through its protagonist's entire life. The first anime adaptation was largely acceptable, but the 2016 sequel is nothing short of awful. Not only does it skip over huge chunks of story (which throws off viewers who unfamiliar with the manga), it looks terrible doing it.
Used effectively, CGI can dramatically enhance animation quality, but used incorrectly, it can make everything look unnatural and weird. Berserk's use of CGI fails to blend in successfully with the rest of the artwork, making the characters' movements appear unnatural and creepy - it's hard to concentrate on the story.
The Deadman Wonderland anime started off great. The show depicts the horrifying world of the Deadman Wonderland prison, where vicious murderers compete in dangerous and degrading games for onlookers' amusement. On a class field trip, the main character's peers die; he shoulders the blame for their demise. His sentence is death row at the prison.
From there, things start to go downhill. Rather than thrilling the audience with fresh horrors, as the manga does, this anime devolves into increasingly meaningless action sequences before ending with little to no resolution.
A common complaint about the Rosario + Vampire anime is it's a silly, directionless harem show, spending its energy on fanservice instead of advancing the plot.
This would be fine if the original manga were a fanservice-based experience - but it wasn't. The manga offers a genuine narrative with finely detailed characters. It delves into the backstories of a main character's family, something often left out in fantasy anime.