Oh, that makes sense. Yeah, I think you'll just have to tell the player there's multiple endings, and let the interested ones find out on replay just how different the story paths are.
And, well, that's the thing. It doesn't have 'a' plot, so much as a whole bunch of potential plot arcs that try to hook you (but you can generally choose to ignore). The ultimate goal is to create something that's more-or-less infinitely replayable, because there are so many possible paths... and as you're playing, I (and hopefully some other writers) are still working on new content.
The setting is... post-fantasy-apocalyse, I guess? But not in a grim or bleak sort of way. Just that there's some decent-sized pockets of civilization, and a lot of demon-infested territory in-between...
Unless I decide that isn't 'high concept' enough, and go with something else. :P