This game is so great, really enjoyed playing through it. Not sure if you care for it, but I'd love to give some feedback.
1. One of the big appeals of the corruption narratives in these games is that the reaction of the girls to the different things they're subjected to change as you progress in their training. Right now the game is a series of activities, and there's very little reason to go back and redo the earlier activities because they still seem to happen in the same context as the first time you do it. The tenth time you do butt plug training with Nyx, she still says the same thing about how big it feels and she still seems relieved to get rid of it, even though she's been dungeoneering with a buttplug for a long time at that point.
There'd be more of a sense of depth to the game if the older scenes changed with the characters, like having Nyx seem accepting and later even enjoying butt plug training, or being disappointed when you remove the treasure plugs or send her to do jobs that are below her sluttiness level.
2. For a porn game, it occasionally feels a little sterile. The girls don't seem to really enjoy any of the sexy stuff very much (or at least they don't often express it). This is a shame because focusing the conflict between the girls' sense of propriety and self identity and their desires to give into their baser needs is a great way to make the sex scenes hotter, and tie them into the corruption mechanics. The sex scenes instead focus mostly on the goblin mc - sometimes it's just him going "Aaaargh!" over and over again - which, as a straight guy isn't really super appealing. It would be really nice if the sex scenes focused more on the girls' reactions, since at the moment they mostly just seem to assent passively or refuse vehemently and then are sort of indifferent about it after.
Also I'm not sure if this is a limitation of the 3D engine used to make the renders, but the act of penetration itself is more or less never shown. With the outright sex, it's almost always hidden by the camera angle, and for the butt plugs there's a jump between it not being in and all, and just being all the way in. A buttplug insertion scene should have lots of "in-progress" renders, dialogue of the girl talking about how full she is (or how good it feels later in her progress) as well as cutaway shots of her blushing, maybe some funny back and forth dialogue and a goofy or pleasured look of relief when it's in. That's your money scene right there, and it's a missed opportunity that it's just handled by "oh whoops, it's in. Well it's big. Okay 30 minutes passed, take this out", when that's the really good stuff that players play to get to.
Of course, all this is just my opinion on how this game could be improved, and others might have completely different perspectives on what they want from trainer games. Overall this game is excellent - the characters are all clearly distinct in the writing, which is often beyond the capabilities of people who write these games. The art style is odd but fun and actually quite appealing once you get used to it. Really good stuff overall, and I hope you continue to improve it. Thanks for making this game!