Personally I like the drawing, (other then the armpit hair maybe, but tbh I didn't even see that till someone pointed it out), but I can understand the critisim. I really like Nitro's art, like I think its probably the best pixel art I've ever seen in a porn game, but some of his scenes really don't be hitting. Like personally, I wasn't the biggest fan of the scene where Sera loes her virginity. It just looked a bit off to me.
I think that just comes with the territory of 2D art tbh, it can be hit or miss at times, at least when compared to 3D games. 3D has a easier time making their scenes consistent. But at the same time, I think 2D is mostly superior, if not because you can really tell when 2D art gets better within a game. Early scenes in HPMF are nowhere near the quality of later scenes fr. 2D art also can be way more stylized, whereas 3D art be looking samey.
Even in that drawing though, you can't deny Nitro draws flesh really well. This is a random thing I noticed, but everytime Nitro draws skin you can really tell just how soft it is. A lot of games talk about how soft skin or tits are, but they look stiff as hell. Nitro really puts that across visually. Idk how he does it.