Bit sparse on all counts. I hope the mentor is not ugly, retarded, or uncharismatic, as is custom for games. I want to actually believe she'd be turned on, almost no NTR ever does that, they make sure you are intensely aware that he's as unerotic as they come and that it's only because the other characters are even more intensely retarded that anything can happen.
Don't make it raceplay shit either.
But besides that, there's little to say. This is a pretty well-tread premise, it could end up quite good, but this is so early that there's no way to say. Unsure what input would be useful. The gameplay doesn't look promising. Even if you add more abilities so there's some strategy, it is a little dry of a concept. But one the dungeon has more than a single linear choiceless route, where you can actually choose directions and have other events, it could pan out to something good. Could have a minimum delve length of 10 tiles but you can rest and do more in the same area. Resting being an avenue for a variety of events, including full-restoring the fiance's mana by meditating with the mentor, allowing her to be more helpful for the next 10 tiles but obviously being her with him. Tons you can do there. And the benefit of staying in the dungeon longer can be things like checking out the other paths that were generated but not explored, and could be incentivized with things like getting a key to a locked door, where there would be good loot, but you likely won't be able to reach the door and the key all in the first 10 tiles. If you want enough loot to keep paying for the resources the expeditions cost and turn a profit, you have to stick it out longer in there.
Or you can play it safe, sticking to short delves that barely break even on cost.
Idle speculation, I don't know how you'll develop the idea.
I did enjoy a particular RPGmaker game where you had to keep fighting off the enemies before the reach your love interest, but there being several times you can leave her in one place that might be safer than being near you in a particular section, or you might move too fast and just outpace her, and you'll see her render on the side, cast in shadow, as she's getting molested by someone while away from you, prompting you to rush back and save her. I'm not a fan of rape at all, I think it's cheat and detracts from the NTR, but the concept of having reasons to separate and the anxiety of it works pretty well. Maybe in the dungeon, when given multiple paths, you can split up to get much more loot, but if you take too long to rejoin her, who knows what she's getting up to with the mentor. Then again, if you abandon your path right away to catch up, what did you even split for? I like it when there's a real compelling reason to make these choices.
As it stands, there's no deep NTR here, she's a paper cutout of a love interest and he's a black void with no character and there's nothing to engage with. It's just a basic demo of a concept for a game that shows that you as a dev can do something and are figuring things out. And I hope as you develp this, it really grows into something I like.
Good luck.
