I haven't seen an ending this disappointing in a while. I'm going to have to spoil this for you:
Kyōsuke does not end up with Aiko. The manga suddenly jumps from high school to adulthood and you find that she went off to study so she could take over her parents' huge multi-zillion dollar business. So Kyōsuke ends up marrying Shunka, the Chinese girl. While realistically those two would have a slightly better chance of actually staying together, since when was this manga ever based in reality? I mean seriously, when you have a manga where a guy gets superpowers from putting used women's drawers, bloomers, and swimsuit bottoms on his head, I think we can safely say that we're not exactly expecting reality to poke its head in.
Shunka isn't awful, but the problem here is that there was no romantic buildup between Kyōsuke and her, at least not the way that there was with him and Aiko. The entire thing was done so suddenly, I can't help but wonder if this was the result of a cancellation and Ando decided that he'd give a big middle finger to everyone in the office. It's not like there was buildup between Kyōsuke and Shunka the way that you saw with Ranma and Shampoo or Tohru and Kyo. Heck, you don't even have the Ataru and Shinobu bonding you had in the later volumes of Urusei Yatsura, where she wanted nothing to do with him. Our main hero in KHK spent most of his time trying to get away from Shunka, so this was just too abrupt.
I am giving this two stars because while the ending pisses me off, the baby Hentai Kamen was kind of cute. But this will still piss off a lot of people who were expecting this to end differently.
This entire review has been hidden because of spoilers.