So I'm going to be writing a list article about weird monster movies in a couple of days. I've already seen a bunch, but for "research," I feel compelled to watch more (these are the kind of movies I'd probably watch either way, to be honest).
Death Kappa was at the top of my shortlist. This is mainly due to it being called "Death Kappa." I can't really resist a movie when it's called "Death Kappa."
It basically feels like a homage/parody of old-school giant monster movies, though the titular monster is the only monster in it for a while, and so there aren't even any giant monsters for like the first 2/3s of the movie. But that's okay. It means he can get in hand-to-hand fights with the human bad guys in the first half, some of whom wield samurai swords. It's that kind of movie.
The plot? Uh... there's a young woman who has some sort of connection to a kappa monster, who lives in a lake, and is super ugly, but he also has a good heart and wants to protect her. He saves her from some bad guys. Then another more evil monster (who's big) starts attacking a city. From there, it feels like a more comedic take on a giant monster movie.
I don't know if this is even good, but I had fun throughout. I was trying to do some push-ups while watching it (exercise and movie-watching: killing two birds with one stone), and for the most part, I couldn't, because I was laughing too hard at many of the scenes. There's a song that gets played a couple of times, and the ridiculous lyrics (at least from the translated English subtitles) are amazing.
Death Kappa is absolutely an acquired taste, but I think I'm the target audience, so I liked it. I don't know who else I could recommend it to, though.