Yeah, it's 3 separate pieces for 3 parts of a story if you have time to read it, it's up above or on the project page, but the streaming version is just all 3 combined for easy listening - the boat ride is the first part, but I decided to continue the story after the boat ride, which are parts 2 and 3.
The intense part is intentional, there was an encounter with the Yakuza, https://en.wikipedia.org/wiki/Yakuza which are basically japanese gangsters / crime lords... you can think of them like a Japanese mafia. They've been around for centuries.
The Dulcimer instrument you mention is actually a koto, a traditional Japanese instrument, also has been around for centuries, maybe even more than a millennia 0_o : https://en.wikipedia.org/wiki/Koto_(instrument)
The experimental soundtrack you mention is actually mostly Enka music, another Japanese music genre with a long history: https://en.wikipedia.org/wiki/Enka