Well, it's still in "Genre" as incest, not sure why it's not in tags.
Tags are supposed to reflect what is actually in the game, not what is planned. Thus far we haven't had actual incest (nor any real sexual activity) so no tag yet. Developers often find it helpful to include a list of planned tags (either in genre or notes) to let people know just what is coming down the pipe, if only to avoid the shit storm when a certain three letter tag rears its head later on. It also helps people who are looking for, or looking to avoid, other features like "harem, incest, lesbian, femdom".
The developer in this game has chosen to release the demo and updates in small increments. This may increase the visibility of the game as it is brought back to the top page of latest updates every couple of weeks. On the other hand, since right now the story is split between two main characters what we're getting is 40 odd renders for half the story, once a month (80 renders if you are following both mcs' paths). I applaud a dev trying something innovative and new, but this strategy is having mixed success at best based on the comments in forums. A lot of folks may be interested (good female models help in this case), but haven't seen enough to commit to support. This looks like a really good project, I just wish the demo had been released as a finished intro to the game with a little more lewd content.
From what we've seen so far: fantastic model for mother, good models for sisters, interesting sinister background for plot which look like it has some legs for future development; this looks like it could be really good with an improved release strategy/schedule.