It's been a long time since I seen '99 series, but going from Gon's outdoors exams adventure to an arc involving mafia that mostly takes place at night was... not really what I expected! The exam already had people dying tho, so I also didn't exactly place it as a happy kids adventure before that.
Also went from '99 OVAs to manga. I already read a description about the CA arc somewhere that half-humans were eating other humans, so that kinda put it in my mind that the latest arc was some different shit. Then when I finally read it, the uncensored manga violence (or in the case of the tree-top scene, everything covered by black bars which just made it seem even more fucked up) and old characters abruptly being brought back only to be killed off was quite a shock. I did feel it was on a different level than before.
Funny how I usually forget about that Puhat scene. I know the mass-explosion scene is really messed up too (especially in the manga), but that Puhat part really stands out in an arc that's otherwise relatively chill with the (onscreen) violence.