I don't even know if I would call it mediocre.
The art is good.
None of the characters are interesting or charismatic. The worldbuilding is nonexistent.
The dialogue is bland. It doesn't have any of Chainsaw Man's humor.
There's some edgy crap here and there that doesn't add anything to the story, especially in earlier chapters.
I don't how this is the same mangaka that wrote CSM, Look Back, and Sayonara Eri because Fire Punch is significantly worse.