It physically pains me to rate this game as low as I am, but hear me out. Succubus Covenant is a crazy blend of highly polished elements and some of the most tedious crap I've had to sit through in my life. And it is so, so close to being amazing that it's frustrating me to no end. It's lead me to play this game, ditch it, and then pick it back up six months later to do the same thing again a few times now. Everyone who's vaguely critical of this project has mentioned the exposition, so I won't go over that tired path again. No, I'm here to talk to you about sex scenes.
As others have mentioned, the art is very good, if quite samey when it comes to body types. If you like thickset, ridiculously voluptuous women, then you'll get it in spades here. I mean, there's also nothing particularly imaginative going on, in a game about literal monster girls, but I'm resigned to the knowledge that nobody has the guts to even come close to MGQ in sheer weirdness anymore. The addition of animation since I last tried playing this is a step up, I'll admit, though perhaps not for the right reasons.
See, the animation is great. It gives the scenes some kind of eroticism they previously lacked. And that's the kicker. Without the art, or more specifically the animated art, these scenes are as lifeless as the Gobi desert. The writing has gotten better, from what I've seen, in that it's not quite so verbose and clinical anymore, but the scene writing is still quite lacking. They're simultaneously too fast to be sensual, and too slow to be intense. It's weird, the pacing for the sex scenes in this game, is my point. Also, the description is veeery tab-A slot-B problem for a lot of the time, in that it's basically 'Suck suck' 'Aaaah, she's sucking my dick!' and that's kinda it for description. In the aforementioned example, there's no description of her tongue, or how soft her lips are, or how her hair tickles the protagonist's hips, or the soft weight of her head in his lap. And that's just sad tbh. Writing gets underappreciated on this site a lot, and this game is like the epitome of that problem, because I swear, writing good erotica into an RPGmaker window is literally the cheapest, fastest part of your whole game development process.
I've played games like this, which I can't mention by name due to cross-promotion rules, where Succubi are meant to be these horrifying entities that tempt you into allowing them to drain you, often painfully(in the end) to death. What made that work in those, and this one not so much, was the pacing, and the framing for the scene. I recall a scene where a succubus blackmails you into giving her a sponge bath, in one of the most frighteningly tense/sexy scenes I've played to date, because she has something you need to progress, but you don't technically have to say yes to it. In this game, the sex tends to happen 'at ' you, and you have a binary choice of 'use iron will' or 'get the succ, game over'. Then combat happens, and nothing sexy happens during that unless you deliberately misuse your abilities. This isn't a BF game, where you're both having a constant, tense, grapple-fuck of a battle to try to make the other aroused. It's like a very inadequate version of MGQ's system, except in that game the monsters were actually seductive, and actually trying to throw you on the ground and rape you.
That's the kicker, for me. The succubi aren't particularly seductive, and there aren't really systems in place at the moment to allow them to be. Their Succubus charm ability in combat is a very binary 'do you have Iron Will' check. They don't pin you down, or whisper in your ear, or taunt you about staring at their oversized butt, or do anything I wouldn't expect of a half-assed RPGmaker enemy during combat. They have one, maybe two scenes apiece. None of the scenes are super imaginative, especially because the Succubi are not particularly well designed, character wise. Each is a gorgeously sculpted milf in cosplay, and that's lovely, but... can we get some proper tentacles? A mummy's curse that forces you to want to masturbate to death, while she uses her bandages to entrap you in an impromptu sex swing? A milf in cosplay who actually knows how to dirty talk a guy, if you must continue the trend?
My advice is... overhaul the combat. Give the Succubi actual sex/seduction attacks, rather than this generic temptation thing, and maybe even a grab/struggle system. Even if you don't have art for it at the moment, give a short loss scene in text for the different ways you could lose to them, based on the moves they have. Make their drain ability less of a 'use iron will, dickhead' stick to hit the player with, and make iron will more of a preemptive shield against getting charmed, so you can focus on attacking for a bit without the risk of giving in to her 'affections'. Give them little ways to counter it that aren't just 'hit funny sword man'. I swear it's a crime, by the way, to have plant succubi and not have at least one sex pollen attack/scene. If the player had to juggle their health and their arousal, and Iron Will essentially forced the succubus to attack your health, that might produce the groundwork for a system with some kind of tactical element to it.
Anyway, I've ranted enough, I think. I hope it's clear from how long this thing is how much I want to like this game, even if I currently don't like it very much. I wish the dev luck.