The game really never got past its' early stages, so there's limited progress to be made overall. Once you get to exploring the neighborhood phase of the game, you talk to Vivian in the house at certain points of the day and get your sidequests. Once love and/or corruption hits a certain value, you can progress. Eventually, you'll notice the days won't advance past, I think, it was a Monday.
The coding of the game is pretty flawed, so some triggers do or don't occur, hence why you may have seen a scene at an inappropriate time.
The dungeon crawler aspect was cut early on for the location selector.
You can't play as other characters.
Your best bet is to use Unren or any other Ren`Py decompiler to see the pictures and videos.
At this point, there's only one person working on the game and has effectively restarted from scratch. However, the only way anyone would know that is if they followed the discord channel. There hasn't been any further releases as the developer wants to work on their own time and release the final product when they feel ready. As of this writing, the dev hasn't been in the discord for about half a month, but they do go dark for days or even weeks at a time.
