In general, Good paths are pretty mellow, more romantic, made towards MC being a hero and building himself a harem with a bunch of hurdles down the road. Recommended for players that are fairly new to VN's or are more into a vanilla experience.
Dark paths go pretty damn far in their storylines and are really wild, contain more fetishes and whatnot. This route is not really for the fainthearted but nonetheless very interesting because of the duality this game holds.
There are basically multiple stories with different outcomes that vastly differ from each other. In any case, we're working very hard on the coming update, LOTS of cool stuff is coming up.