Free Cities: Origins is a game still in early development, but having played the game for 15 hours or so, I can see that the mechanics and systems are well thought through to future development of the game.
Currently the game progresses day by day, and the stat growth of your slaves is slow along with your income, this is because the game isn't to the point where the developer can coherently add a skip week or month option which is indeed in the works, probably to be accomplished within 3 or so major updates.
Free Cities: Origins has quite a few aspects, most of the focus is on the slave training part, the slaves have many attributes, such as Intelligence, Strength, Dexterity and the like, there is also sexual skill levels, such as Oral, Vaginal, Entertainment, Bondage, and Other. On top of attributes and sex skills there is also, another subset of skills, Education, Melee, Ranged, Survival. Those are going to be used for a combat system in the works, as there is an arena in the city.
The economy system is pretty complex with prices of the commodities change by the day and trending over the course of weeks. You can trade with three different commodities, Iron, Silver, and Gold. At the moment the difference between the buy and sell price is dependent on the difficult chosen and a few other factors, only the easiest mode is balanced enough at the moment to be able to make any money off the market, and is what I recommend to play on if you want to get to what I could call the end game of the current version.
The story consists of you being a slave under a man named Shinatani, he's isn't an abusive master and only punishes you if you don't obey his edicts, which are mostly working your quota for the day, he has three other slaves, that are female for you to interact with plenty of sex to be had, two of witch you can control to a certain extent, sending them to work at a brothel, or working in the mines, studying, or training with the army in the barracks.
Overall, even though the game isn't polished, nor is it that close to being finished, what is there and the potential of this developer and their game is awesome. The mechanics in place and the development plan are very organized and thoughtful, as long as this projects continues it's sure to be a great experience.