At the moment, what sticks with me most from Soul Blazer is the character of Doctor Leo. The entire time, you explore worlds that are created by him. Not only do you spelunk dungeons created through the use of his capture pod things, but the people and animals you meet are all influenced by Leo. In this respect, his house makes the perfect setting for the climax of the game; Soul Blazer is about exploring the world that Leo has created, and what space belongs to him more than his very home?
It's the kind of story you see in Heart of Darkness and Citizen Kane. The protagonist is a boring, empty shell of a guy, and he provides the lens through which you can see the main show, be it Kurtz, Kane, or Keo. Leo. And, much like (Castlevania) HoD and CK (Louis), you also observe networks that feel the indirect influence of Leo. The second world marks my favorite example of this, as apparently Leo's pet dog led a community of woodland creatures. They all speak fondly of Turbo, but you never hear about Leo himself--yet, it is Leo that shaped Turbo.
Down to his name, Leo is a creator--a god among men. "Leo" is the Latin word for lion, a creature often taken as a symbol for the Judeo-Christian God.
I find it curious, though, that no one ever speaks ill of Leo. He himself regrets creating the Evilmatic 5000, but no one blames him for their capture.
also why is the dog named "turbo"