I guess Holdover is technically classified as an "adult" or "hentai" game, but what little erotic content there is seems bolted on to an otherwise standard "platform hell" game that is more about having a somewhat creepy sci-fi atmosphere than it is about the usual sexual content.
The setup is that a young girl (who looks like a combination of Samus Aran and Roll, just chestier than either) with a deadly disease has been put into long-term cryogenic stasis by her wealthy scientist father. She's also been equipped with ankle bracelets that are somehow working magic on her while she sleeps and curing the disease, but by the time they get done it will be hundreds of years into the future. Of course, during this time, the world utterly goes to shit (yet no one messes with her capsule somehow) and the girl awakens in a crumbling, Aperture Science-like facility that is mostly flooded and also patrolled by laser-firing security droids.
Alas, those rejuvenating ankle bracelets have an unforeseen crippling downside -- they're heavy, making swimming through the flooded facility an extra-hazardous affair with almost no room for error. Thus our "platform hell" setup. You'll proceed through screens full of deadly spikes and robot lasers, and frequently dip into underwater sections where you're given *just* enough time to get through if you make all the right moves with no error whatsoever. It's a lot of try-and-die, as you're often thrown into dangerous situations you have no opportunity to size up beforehand. There's no auto-respawn, but fortunately you can save or load anywhere except on a screen full of water, otherwise the game would be unbearable.
Even with saving and loading, however, it's still pretty brutal. Part of that is the fact that it's short, taking maybe 30 minutes tops to run through if you were able to do it without dying somehow, so the difficulty pads out the playtime. But it also seems to be an opportunity for designer Fox to bolt on the erotic content, as he seems to have some sort of an odd thing for girls in swimwear having to go through dangerous situations in which their suit gets partially ripped off, and ALSO they have to frequently be at risk of drowning. I guess when your fantasies get this complex there's nothing to do but design your own virtual worlds to accomodate them? Whatever the case, the "erotic content" is limited to our girl's clothes getting ripped when she takes damage, which leaves her technically topless/bottomless, though it's Barbie doll style with none of the really vital bits depicted. She also finds a way to just barely cover said bits in the portraits, so there's really no *true* nudity in this one that I'm aware of, nor are there sexual situations.
Odd clothing destruction/drowning combo fetish aside, I actually thought this was a good concept with impressive atmosphere for how basic the art assets and the gameplay style are. Problem is it's just too demanding and irritating to play unless you're really, really into those Mario ROM Hack save-scumming style platformers.