Game needs to be able to be played on more than just Windows OS platforms. Win, Mac, and Android compatibility are the standard. And if you're using this engine, there's a program provided by the engine source just to convert the Win version into an APK. Worst part? Unreal Engine is not compatible with all Windows OS devices, only the middle to higher end ones. It's a known issue, so most developers just ignore it, and it's probably for the best to do the same. Still, I am not the only one to recommend widening your audience base by creating game versions for other platforms. You can even do like some on other game sites (itch.io, etc) and convert it to a Web browser version, either for public or just demo (though demos only annoy people). And that's my two bits on it.
Otherwise, for a new game, it still seems fairly limited, but with a lot of future potential... IF you fully develop the standard and classic hgame mechanics. Basically, no sex without consequences and no sudden Game Over instead of infinite continuity of play.
And I haven't even touched on possible game content expansion if you try adding mechanics for mutations, mutagenesis(mutagen), mods(modification/alterations), etc. (See: Trials in Tainted Space (TITS), CoC, Parasite Infection, Accidental Woman, etc). (For game content, I highly recommend.)
(I'm going to list some things that can and have gotten developers in serious trouble via the global crackdown - much of which was removed from F95zone because of it before 2020, etc. But new devs often don't know about it.) Otherwise, if you're going the monster sex route, try looking at hgames from 2010 - 2018 for ideas if you can find them (global censorship hit somewhere between 2015-2018 and the censored versions didn't show up until around 2020, replacing the originals), or games like Princess&Conquest (for a less graphically offensive example).
(Tip: avoid these things like the Plague: Loli, Shota, Cannibalism/Vore (the whole Vore genre was started by a group of real life cannibals in Eruope in the early 2000s(?) who traveled & cosplayed as Furries until they were wiped out by law enforcement), Filth(sewage stuff), and some others.
You can probably get away with some Besti (bestiality) content if you don't call it that and avoid obvious animals, although technically sex with anything nonhuman is besti - you're using parasites/tentacles/alien concepts which is besti by default. This is often listed as: Monster Sex, Interspecies Sex, Cross-Breeding, Pedigree, and Interracial Sex, and others. (If it is just human+animal only sex, then that is besti, but also called Zoo (zoophilia) and no platform will allow that tag label - indeed, most of the labels listed in this comment are banned in most places, but you'll still see it there. Why? The description of game content doesn't flat out say it or indirectly avoids it (like incest games renaming Mom/Son to Landlady/Tenant). It just depends on how you handle it.) But use the [What would Patreon do?] question when wondering about content - if Patreon would ban your account and report you to law enforcement, it might be something you want to find a work around for. Just saying...
(I actually recommend trying to use these mechanics as the market for them used to be rather large - it wasn't considered a finished hgame without it)Things that often get requested but was once listed along with loli & shots content legal-wise (it is why these are rarely seen in games today, but are considered acceptable legally to a point now, I think) are: pregnancy, births (graphic births might be a problem, though), etc. It allows for the use of random npc/monster/new characters to be generated, thus expanding both possible game content and an element of randomness.
Questionable content, depending extremely on how it is handled: insect sex/ovipositor/eggs (most Asian countries label tentacled monsters as insects), incest, male pregnancy, gay sex/shemales/traps/Futa/Futanari/etc, Furry content, etc. This can be treated as bad as loli/shota in some countries, or worse. Germany had a group actively hunting developers of gay games at one point. And China executed devs for loli/shots stuff...
(Don't recommend these) I'm sure there's more I can't think of, such as any violence S&M junk, slavery, torture, etc. (Think Mad Island - just looking that one up online can get you arrested in most countries, by the way, and it's still available, which is weird.)
Personally, I would highly suggest developing several of the mechanics for great interactive BattleSex: cinemas (think FF7 style in-battle power cinemas), possible interactions during battle, corruption/purity game paths, interaction between party members during battle,...and...damn. It slipped my mind. Tails of Desire used to have a great BattleSex setup and so did Warlock&Boobs & the older version of Claire's Quest, but they got rid of them a long time ago. Now I can't think of ANY hgames with barely okay BattleSex mechanics. Maybe someone will recommend a few.
Can't think of anything else offhand you might want to know about...
Games for your interest? Try Tales of The Unending Void. I'd list some others (Secrets of Hokwiton,Parasite in the City, etc, but they've since either been gutted or abandoned - and I can't actively recall the jrpgs I keep thinking of. JRPG games like that all ended up censored either with pixels or shadow sihuoettes of the monsters instead of the other graphics, such as the censored version of Jumble Strikers (can't find the original uncensored version anymore).
For art design, you might try some non-hgames: the game designer/illustator - Kim Hyung Tae - for that old game series Magna Carta comes to mind...
(Just...don't do like some games: add a lot of stuff and then strip it all out, like Tails of Desire, The Rise of Gruk, and many other games did. Yeah? )
ANYWAY! I wrote all this crap - and I really only started by wanting to say one thing:
Good work!
I look forward to the finished game!