Uh, what are you expecting? What kind of question is that?
Not all games on Steam are 'finished'. Are you unfamiliar with their whole Early Access program that they have been doing for over a decade now? What a dev releases to Steam, and what other versions that may or may not exist and get leaked here is going to be different for each and every game. There are plenty of uncompleted games on Steam that have also been leaked here. Just being on Steam is zero indication of a game's level of completion across the board, not just for amateur eroge games.