Jibaku Shounen Hanako-kun is a good anime by itself. I am an avid fan of the manga so I was very excited to learn it was getting an anime adaptation. However, it was fairly disappointing.
Story: 6/10
If you just watch the anime by itself, with no manga context, then it is a very good anime. However, the amount of crucial arcs that are missed out from the manga is insane. It throws the whole pacing of the show right off. I was really disappointed in this. I understand that there was not enough time to fit everything in, but if this was the case then the planning should have been way better. Or maybe even add a couple extra episodes to make it actually flow properly.
Art: 8/10
The art and animation of this show was breathtaking. It is unlike anything I have seen before. The style, the layout, the animation, it was all beautiful. Some shots in the anime do look a bit weird and unproportionate, but apart from this I think it is a very good representation of the manga.
Sound: 10/10
The voice acting cast in this were amazing. Hanako's voice actor especially fits the role so perfectly. The music was also amazing. I cannot think of any flaws in this area.
Character: 7/10
The only reason this is not a 10/10 is because of the arcs that were excluded in this show. It really ruined some of the potential character development, especially between Kou and his brother. Very disappointing. Though, for what it was, I guess it was okay.
Enjoyment: 8/10
Despite the major arcs being excluded from this, it was still a very good watch. The voice acting, the visuals, everything about it was amazing and I would gladly rewatch it.
Overall: 7/10
I think you should definitely watch this, however I would recommend you read the manga alongside it in order to get the full story without missing out on anything.