Great question. The short answer is as long as it needs to be.
Here's the long answer. I want this to be free for the community to enjoy, but this is a major time investment on my part. When I get more patrons I'll add even more content. As it stands I plan on doing at least ten dungeons and three different romance endings. The more support I get on patreon the bigger the game will be.
Each dungeon will culminate in a sex scene and each romance option will have various romantic encounters.
I've already added a few minor NPCs that can be romanced as well for one night stands.