I wouldn't necessarily say it's wrong for a lot of games, but for a visual novel, that can definitely be damaging to sales. If an entire let's play of cities skylines 2 came out, showing every progression milestone and all of the features, I'm still buying it on release. If anything the video would help cement that decision. For a visual novel? Well I've already seen the entire novel so, who cares. Generally though, if you have early access to a game before release, you should be respecting the developers guidelines, and are likely contractually obligated to do so.