i forget what version is up as a demo here, but i'll give a go at answering you.
sex xp and good/ evil points are mostly uncompleted mechanics. however, getting pregnant and giving birth provides you with a minion, the type is determined by what kind of monster did the impregnating. parasite infection just gives birth to a weak monster.
the fountain on the game page is at the "hub" church you're at between runs, though i think that specific graphic of it is unique to the tutorial.