clearly, I did not. When creating a visual novel all voice should be loud and clear and music should be low and calming.
While changing the volume in the settings does solve the problem on an individual basis, I don't think it's really strange to ask that the standard settings at least allow you to hear Death speaking. It would improve the game ever so slightly. If I had to compare it with anything, it's like a typo: it doesn't ruin a game, but it does make it seem a little less polished.