Hello there,
well i have only played the game to the forest camp point and have done two adventures and some other stuff so apologies if i get something wrong.
well, at first I found the writing a bit odd but soon it grew on me along with characters, your pretty good with character development and pretty decent dialogue as of now occasionally the MC reacts to information in bit of an odd way and sometimes it feels like he has more information or i missed something in a conversation aside from that great dialogue.
character design is pretty good they look nice
Plot is a pretty cool one normally the type of character the hero is that type is used in other shows to uplift the protagonist to show the wannabe hero against the true one, here our hero does have heroic qualities and wants excitement or wants to be a hero, sort of like Nobody(American Hollywood film) he passes his test of mettle and decides he wants more (also who tf is just gonna let a creature of aether go after seeing it and fighting with it) raised by a mother and father that were not given art but whom i would have loved to see more of ( mad scientist and brute warrior sounds very fun) and i see someone read HP Lovecraft the abyss seems interesting so lots to see lots to do
now lewds i feel like they could be improved, the best ones i have seen so far were the ones in the beginning with one of the two succubus' (by the way was the promise of a threesome with those two just words?) or one of the after ones tho even those seemed to suffer from lack of art. I feel the more recent ones at camp are not very descriptive and having absolutely no art or animations depicting anything is disappointing for improvement i recommend improvement of your description of the acts and some art and/or animation (by the way i think the best in terms of description has to be taking Sarah's path after getting home)
also by the way why does Sarah's outfit only change when we go with her i don't see why the hero's mother would not give her a change of clothes at one point
sex battles, interesting the demi-humans here are a colorful bunch regardless i know you said you will add magic but once again i feel that you need to be more descriptive (apologies for being vague about the writing and description of the lewds generally I'm specific about the problem but if you want i can try to give some examples) and once again art and/or animations would be lovely and also i think if your doing one in camp or somewhere i think there should something for whether you win or lose whether unique rewards,dialogue,XP or scenes is upto you
this might be me but i treat the sex fights as just another fight tho could just be me but may i request a QoL change to the sex battle UI in the personality tab you could place whether being gentle or rough is more effective and what position are they weak in, this would be unlocked as you fight them and learn what their weaknesses are.
aside from that story seems to be great just lewds to be worked on (ironically)
i wish you the best of luck upon your future endeavors and your lord of mysteries but with a harem and in a fantasy world
-Infinite