I was considering the other day how all of the Japanese and Korean players I have seen play cultured have had broken sound, and I was considering the differences between culture and K2 and other games produced my Japanese players such as permanence 2.
The main thing I noticed was that they other games all used the DLL, and that maybe that had something to do with it, although I have no way to be sure. I just thought I would bring it up as your engine or the games made using it might also suffer if this is the case.
The problem with cultured's music is too inconsistent to really be sure what exacly is causing it. If I would have to guess it would be because there's too much sprites, backgrounds and sounds stored in the memory. So when it tries to load music, it can't fit certain songs into memory.
When you look at a game like Kamilia 2 & Kamilia 3, it doesn't even compare in number of screens/rooms. The only reason why it would feel like a bigger game is because you spend so much time learning and fighting the bosses.
I'll see what I can do about the DLL though, I've been wanting to make the switch so people don't have to download and install the extention.