There's nothing I can think of to critique this show. It was just a good revenge story with a good message and good main characters. The opening is amazing too. It's got a story, some comedy, action, and hits in the heart. Romance would have ruined the anime, so that was a good thing to leave out. Even the comedy had it's moments where it wasn't forced but did enough to lift the mood. Very underrated, so it deserves a chance to be watched.