Slavemaker is a fan hentai parody of the game ‘Princess Maker’. You are a slave trainer in the kingdom of Mioya. You are contracted to train a girl to become the ideal slave. She will be trained in many fields but sex is a significant part of the training. Each girl has a training time before she is turned over to her owner and in that time you need to try have maximize her abilities.
There are dresses and other items that help this, and also potions of various effects. Part of the interest in the game can be learning what these things do and where they can be found.
The girls are various characters from anime and games, their personalities will be similar but not identical to their source. Also note for this game they are all 18 or older (despite the occasional school uniform you may see).
Some more extreme hentai elements are in this game, including bondage, rape, ponygirls, tentacles and dickgirls. All of these hentai elements can be disabled from the Options menu.
Also note this is fan or doujin game, so is not for sale in any way. My apologies to the original copyright holders and artists. No offense is intended.