This game seems interesting. CG are well-drawn but I just can't ignore how the mom has the same expression in all the preview pics. Is that an on-going trend throughout the whole game? It makes her look sorta lifeless
Cause it isn't well drawn.
Looking through the game, it is pretty clear that the artist is at the level of being able to decently copy porn or other hentai artists they're a fan of, but entirely lacks the more fundamental skills to establish their own artistic style. This is why the quality is all over the place, as you swing between stuff created using reference material or tracing, and stuff where the artist is trying to 'wing it' on their own without reference. You can see it in the environment, and the characters.
Ignoring the characters (and their mangled or missing hands), this is actually pretty decent background art. You have a good composition that looks mostly looks like a modern living room. Consistent line work, and the perspective seems solid. Now if the artist was able to make this up entirely whole cloth from their imagination, that's pretty solid work. Also if that is the case, then you should expect the rest of the background art to be of the same relative quality.
It is not the same quality. This is what leads me to believe that the living room is based off of reference material (perhaps even tracing a photo of an actual living room), and this bathroom is the artist 'winging it'. For one, the perspective is much weaker and inconsistent. Now in the living room they were able to do rounded tables and the soft edges of pillows, so surely the rounded edges of a sink basin and water faucet should pose them no trouble, right? Wrong. They're all either a mushy mess of squiggled lines or sharp edges. Unless you're working on an installation piece for the MOMA, sink basins don't typically look like that. Also, you can pretty clearly see aliasing of the linework on the toilet, leading me to believe that it is clipart that was stretched from its original resolution to something much larger than it was originally intended; that's what can cause those visual artifacts. If the artist had actually drawn the toilet themselves and to scale, there is no reason for the line work to be jagged like that. Also, there is just a random frumpy looking shower head at the top there, and no bathtub, shower stall, or even a floor drain to go with it. Plus, all of the bathroom tiles are inconsistently sized rectangles rather than squares, cause the perspective lines are being drawn pretty willy-nilly. So yeah, overall, a pretty poor composition; and not at all up to the quality of the previous living room. These are some of the things that indicated to me that this bathroom composition was the artist 'winging it' without any reference material to copy from, and it shows.
Again, another solid background. Good perspective, looks authentic, and I even appreciate the attempt to mirror/flip the right wall and door (but notice, not the left wall or stairs) done to make the floor appear so clean and polished so as to be somewhat reflective, even if the angle of said reflection is off. Again, seems like a pretty solid candidate for slavishly adhering to reference material (perhaps even to the point of tracing).
But the people? Well, hands are hard, so they're all mangled or partially hidden. Pants? Starched so stiff that creases are non-existent. Perspective? Not really a thing. They largely look like they're being drawn in three quarters view, but their far shoulders stick out way too much, to the point that if you were to drawn the underlying skeleton in those poses it would look broken and disjointed; as in you'd have to literally dislocate the shoulder to have it stick that far out from behind the chest. Faces? You got one generic anime boy with entirely black soul-less eyes, and someone who looks like they were a rejected background extra in a bad Family Guy knock off.
Okay, so now we have a pretty decent composition. Perspective and proportions look good, and crucially, the one not hidden hand actually looks like a human hand. We're still hiding the feet, but feet are hard, ask Todd McFarlane. Again, it is hard to believe that the same artist responsible for the frumpy looking goons in the hallway was also responsible for this. Which leads me to believe that, once again, they're copying someone else's work here. Not only is their grasp of human anatomy, perspective, proportions, and composition wildly inconsistent; they kind of give away the game when they try to 'wing it' on top of their somewhat decent stuff.
Now her left hand is back to being deformed and mangled, as is par for the course. If the artist is capable of drawing a decent looking hand while finger banging, how come they can't draw a decent hand while just cupping it over some genitals, a much more basic pose? The simple answer is, they didn't have a reference to directly copy off of for this part, where the woman is trying to cover themselves in shock rather than showing off, so they had to 'wing it' for the hand.
Now we're back to a good looking hand, but with a much more complicated pose. Again, that inconsistency in quality makes little sense outside of the artist copying other people's work or slavish adherence to reference material. It belies a lack of fundamental drawing principles. It looks like work from someone who is self-taught, and did so through copying anime/hentai that they liked, but otherwise have zero formal art education. This is not the work of someone who has ever taken a life drawing class or practiced drawing nude models in person, stuff you'd do in college level art classes. It's the level of someone who got really good at copying anime waifus on their notebook covers in high school, but absolutely stumbles when they try to do anything original. The artist is proficient enough to build upon someone else's foundation, but not enough to make their own foundation to build upon. Every time they appear to 'wing it', the resulting work is far worse off, and it leads the visuals to have a very inconsistent quality.