The only thing I’d like to add is, getting a lot of views/downloads the first week a game is released, and have them reduces the following days is normal. It happens on all games.
Apart from that, I would imagine the 18+
option is a tricky one. I don’t know a lot about the Itch demographic, but wouldn’t be surprised if there is a high percentage of young users, or users that may not be looking for that type of content. I have no data to back this up, just speculations.