As promised
Night Mirror . In no particular order.
The breasts in this are too high (this is quite common mistake). In addition to this, the body proportions are a bit more faithful to the show, but don't exactly match the rest of the art perfectly. The arms bend funnily, and are a bit out of proportion. The nipple colour is a little too dark. Here's the closest I could find in a brief search of scenes:
Notice how the breasts are slightly further down, and farther apart. The shading isn't uniform underneath the breasts, and disappears in the center.
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Jessica's mouth is too high. A line or two could be added to define the hips / pelvic bone. And she's missing her belly button. The shoulders should probably be more relaxed, and notice how in the original art there is a dip between the shoulders and the neck.
Boobs are slightly too big, and too far up. Shoulders are better, but don't quite match the perspective of the chest downwards. Jessica is staring into empty space, I suggest moving the eyes to look down to make it look more human (this is a super easy fix)
The body is a little contorted, her face is almost facing backwards from her ass, but all in all, not bad art. The shoulder dropping / arm coming forward could help, but I'm splitting hairs here. The thighs are probably a little too large compared to the ass.
The bum appears flat here, and the breasts are a touch too far up. But this isn't too bad at all.
I suggest replacing jessica here with the side pose I posted earlier, as it's almost a complete match. If you wanted to change this one, move the left breast to be less in the center.
The blue womans breasts are a little high.
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Looks really good. The shading on the center breasts is too dark, and should be less to match the other two girls. If the light is coming from above, there would be less shadows than the other girls, not more.
Head's way too small for the body. Breasts too far up, and nipples a bit high maybe (if they were that far up, they'd be pointing upward I think). Neck has same problems discussed with shoulders earlier.
Breasts too far up, the body also looks a little rectangular? Perhaps the back should curve into the bum earlier? This one is hard to judge.
This one looks great, but the closest thigh shape isn't great, and everything below the knee becomes really weird. The perspective is a bit wrong, and it's probably make more sense if the legs were more flat against the bed. Currently her calves look about half the length of her thighs.
The colours on the private parts all need adjusting. They're a bit too saturated probably? Morty's penis also looks like it has been flattened in most of this scene. The sex obviously doesn't really work from this angle, so I see what you were trying to do making it curve upward, but I think this might be one of those times to forget the logistics and make the penis more 3d, perhaps by making it come from a bit lower on morty. The right(from viewer) nipple is a little misplaced and missized.
I hope this doesn't come across negative, this is a lot of what I do for a living. I just hope you find it constructive and comprehensive. You've done great work here. If you'd like, I can do the other new scenes.
Thanks again for the game.