Many PC-98 "adventure" games can be easily beaten by simple trial and error. This is not one of them, you need at the very least, to be able to speak japanese. The sheer array of options is mind boggling and often you have to tab over for pages of possible instructions.

Art style is the typical rough low-res Game Technopolis style, I didn't see any adult content, but it's quite possibly there, as most of their games contain it.