Mertian
Well just done play of update so lets try to review by parts(so other people think of it as spoiler). It's mostly personal so wait for more ppl for better outlook probably. Big wall of text ahead.
Battle mechanic:
well currently it it's not great to be truthful, but that's given as changelog said this is more of mechanic test. Coin mechanic is interesting - seems to be replacing normal attacks or more of replacing typical rpgmaker crit chance(not sure how will luck stat work with this), but even with the heads most of time the battle takes like +20 turns. I'm guessing it will rise with lvl, otherwise maybe try making it act like multiplayer with smaller value and spawn another coin up to x(choose number, so 3%+3% max hp additively or something else). Perhaps some type of leveling talent? Depends on how much work it will be, given solo dev-ing and not complete combat currently, if too much or takes time from making content better skip(actual need will show itself once we get the full combat experience, do we need to lose few times to get strong then win, some bonuses for losing too much/winning easy etc).
Battle music:
nice as always - had to tone it down a little though due to loudness. Probably weird to say, but it might be too artistic? Can't really specify.
Battle visual effects:
Good. Mostly the subtitles(appearing text) as it's pretty rare to see such things. Seen them mostly in japs games. Might to speed up it a little though and if possible it might be good mechanic of overworld(non battle) for some specific events(magical talking crow/possession/madness....).
Seduction mechanic(mechanic only):
You might try to make the choices random, ie give up is now always up so maybe try shuffling it if possible (50% time 1st option others 2nd option instead of standard NO/YES). Also when you click seduce first on body part x, the npc might go for 2nd seduction attempt on other body part - kinda time wasting. Can't really suggest more as most of ideas are katalist things(multiple seduction/graples with possibility of failing) and people are already saying "katalist clone tm"
Seduction sounds:
might get back to it later
Art:
Better than AI due to not giving that fake ass vibe, but you kind of need to get better as some of it shows during scenes(Most of art is good, but when people look for details its does show in some places, generally good though(ppl here fapped to way worse

)). But i'm sure it will come with time and practice.
For most basic things like sausage fingers (I'm not artist, some yt video guide or even trying to trace someone else work(parts only, no plagiarism! well maybe if hot and given credit) would probably give way more value) - just try to create joints - finger are fattest at those parts so you will just have to remember to slim others down, add some small darker lines as skin crease/folds(applies to things like neck(+shading) or wrists) and voila.
For main traveler pic during 1st phase(don't remember 2nd now), you might try to slim lower underwear from above(more of V letter than U?) - kinda unsure if they are panties, spats or something else.
music during scenes:
Probably personal thing, but couldn't really get into the scenes too much cuz of it - kinda used to typical rpg [version] maker music during them or even just sound effects without music. You might need some more people to say something bout it.
Scenes:
Weirdly the best one for me was probably footjob, mostly because of after effect dirt appearing again(loki got tricked lol), but boob smother with bigger breast is also pretty good(kinda weird end to that one though). All got that telekinetic-portal dick handjob, but lost the opportunity of handless orgasm - by that I mean of only either friction/smell|taste/act itself(idea?). Cloning op.
Following is kind of hard to say without looking at game to compare but perhaps some more narrator text than pc-npc talk.
Phone:
nice. I used the save to time skip so i'm unsure if the previously made dialogue choices with characters had any effect or we aren't there yet. haven't tested fast travel
Visual Filter is pain, but someone might like it. I would say it might be better for plot scene than normal gameplay but to each their own.
Bug:
struggling during the special attack in (or was it evading?) the 2 phase makes traveler dissaper(standing cg) her attacks/seduction shows.
About fetish scenes - you might check out if you had made correct if statement(so if there fetish changing scene it will either turn on entire scene with fetish(so two version of scenes, but if multiple its pretty bad idea - 2 fetishes in one scene is 4 events/block of text) or normal scene > fetish switch check and few lines with it(text, cg change, sound) > back to normal scene > repeat until scene ends for every fetish).
I think they went like below in rpgmaker but unsure about mz specifically:
normal
normal
if condition something
.........do something
......... ....
.........do something
normal again