Having played a decent amount of Hero's Advent at this point (finished a mostly pure version of Max's route and started on Kody's), some thoughts on it so far;
>Corruption gating
My biggest issue with the game is how it treats Corruption as this universally bad-wrong thing that's purely evil and having any amount of it over 5 at most is a fast-track to a bad outcomes. Not to mention that all of the options that give you corruption make you into a complete asshole. This would be fine on its own, just some bad ending mechanic you have to avoid...if the game didn't lock all of the NSFW scenes behind it. Despite being a porn game, pretty much all of the porn is locked behind Corruption thresholds to get certain scenes and if you don't meant the threshold requirement, too bad - you need to replay and try again. Likewise, the reverse is true where you need minimal to no Corruption if you want specific scenes, and that means basically no lewd or raunchy behaviors at all. The game has over 100 CGs and most of them are gated in this manner.
It gets even more absurd when you approach the end of the first act and the game basically locks you into a sequence where no matter what you do, you fail and fuck up but to what degree changes based on your Corruption level. If it's too high, then you end up stabbing Alisa, your surrogate mother figure, straight through the chest due to a bad guy's illusions. If it's low, then you 'only' break her concentration and she's forced to shield you as the protective crystal she was sustaining collapses atop you. Regardless of outcome though, you get brought before a court inherently biased against you and no matter how good you were throughout the run, you get viciously exiled and sent off on what's basically a suicide mission. Oh, and the outcome further changes if you didn't bond enough with various characters beforehand or you chose corruption options in their interactions that damaged your view in their eyes.
>Time
The game heavily time gates all the interactions you can take. You only have a limited number of interactions you can make in a given day before it ends and this harshly impedes your ability to see certain scenes or bond with certain characters, basically forcing you to keep dozens of spare saves if you want to see everything. And again, you NEED to bond with certain people if you want a mildly less shitty outcome come the end of the act. Doesn't help that there's RNG aspects on top of everything else.
>Characters
I actually like most of the characters. They're fun, entertaining, and they feel distinct from each other. But I genuinely feel that they'd probably be better off in any other game or if the game itself was less strict on fucking you over for wanting the porn in a porn game. Dave especially feels like he'd be better off in any other corruption-focused game that doesn't punish you for wanting to indulge in one of the chief mechanics of the game. The others too, but Dave is most notable simply because he's the viewpoint character that the plot revolves around.
>RNG
I mentioned this before, but the RNG aspects behind how and where you can trigger specific scenes is really annoying. Not only is it based on what stats you have - those being your Confidence, your Shyness, and your Corruption - but it's based on interactions you've taken with them before and you can screw yourself out of scenes that way. Not helping is that the RPG battles in the game also have scenes tied to them that you can miss, usually because your companions are so strong that they can two-shot most enemies.
>Difficulty
Combined with the above, the difficulty can massively swing from easy as balls to borderline impossible with no space inbetween. This is especially true near the end of the first act, where going a specific route can pretty much softlock you because the final fight before the end is so hard that there's no way to beat it even with your selected route partner. There's also seemingly no specific reason to go that way despite the narrative presenting it as a choice, so you're really just fucking yourself over for no reason.
I'd love to like the game more than I do, but it really does come across like it wants to be as anti-lewd as possible and punishes you severely if you don't want to stick to what it expects of you - that is, being as pure as possible at all times at the expense of any NSFW encounter.