Re: What makes you play H-Games?
As for action games, the only action H-game I've enjoyed as a game so far is Unholy Sanctuary, which I think is the only one with cohesive game-design. The H-content wasn't up to par, though. The closest an action-H-scene has come to what I look for is Hounds of the blade (passable sound+in-game animation+contextual dialogue+extended scenario). Other than that, either the animation, sound, or something else is usually bad in action games thus far.
The sad thing is, if I list the games I enjoyed overall, there are very few. 2, rpgs, 2 VNs, 2 action games, and that's only if I'm being generous. Rather, it's more like those few games showed me the potential, and now it's just hoping time and time again that something will eventually meet or exceed those expectations.
I can certainly get where you're coming from there. Whilst I probably wouldn't say I've only "enjoyed" so few, I'd definitely say that incredibly few really ever satisfy what I'm looking for. That bit about potential rings very true.
The difference for me though isn't whether I "enjoyed them as a game", but whether I feel that I "enjoyed them as an H-game". Far too much I feel that what's available falls towards two categories. Games with some h-content on the side, or H-content with some game elements on the side. If I want to play a good game, I have thousands of regular titles to choose from. And if I want to see some hentai animations, you can normally find far better than anything you get in the majority of H-games.
I hope you don't mind, but I've always used your own Kurovadis as a prime example of the former. An enjoyable game with superb conventional game design, but one where the H-content essentially sat on the side, and could even be removed without really effecting how the game played.
"Barrage" is probably another example. A fun high action game, but with overly simplistic H-mechanics that don't really mesh that well with the game. The only way to trigger the H-content being to run into enemies when under 20% HP, despite the fact that most enemies will just shoot you on approach and never make an effort to grab you themselves. Asides from that it's just stuff in the background that could readily be re-skinned for a SFW version. The benefit of this kind over the other kind, is that they tend to do a bit better providing at least some emergent narrative context for the H-content, such as "I screwed up here so now I pay the price" but ultimately it's entirely up to the player to imagine it.
On the other side of the spectrum, you've got the kind of games that are essentially little more than an H-animation slide show, with often clunky bare bones (and often minimal challenge) "gameplay" padding it out, typically expecting you to deliberately just lose on purpose repeatedly. They also tend to be incredibly uninspired regarding how to access the H-content, such as it simply triggering any time you so much as touch an enemy, and with the ability to struggle out having a 100% success rate. The worst of these like to fill the game with instant death pits as an excuse for level design. The benefit of this end of the scale is that they tend to put more resources into the H-content, with better art and animation quality, sometimes sound, which obviously has it's value. But soon enough you're back in the "game" deliberately blundering into the next animation, with next to no context to get you involved mentally or emotionally.
Trying to think of examples that meet the middle line here I'm looking for is tricky, since like you said, most of the ones I've enjoyed the most, have still really only been because they've shown the most potential. I'm also reluctant to try and name any since I've probably just come across as really picky and judgemental. But I hope people understand what I mean here. ^_^;
I just want more genuine "H-Games". Not mega man with sprite sex, and not HQ sprite sex with clunky instant death pits. Something where you can't just remove either side, and still have main appeal of the game in question unaffected. It's a entirely unique form of game design, that doesn't exist in the traditional games design world. And for the last 10 years I feel like I've watched countless authors struggle with it in their own ways.