Here's some context. It's an older version with some weird pixels not fixed. But it's closer to how it will be used in game.

This is great. The teeth are really well done. After studying the piece that's the part I'm most impressed with (or rather jealous of). And the shadow on the neck throat area has some well done shading too.

The things that stand out as being problems:

1) Hair. But I definitely see the decision to use less detail. I still wonder what a bit of detail would do.
2) That bright highlight above her right eye stands out. It's easy for me to say simplify it, but maybe you've already tried that and you settled on what you did.
3) The watch was actually the first thing that stood out to me as not working, but then I looked at the original photo and I'd say you did a great job conveying whats there. In fact if you enlarge the photo it starts to pixelate anyway. So I'd say if you are trying to copy the photo exactly you did an excellent job, but if you want to take artistic license, I'd simplify that too so it reads better. It reads as a bracelet now instead of a watch.
4) I go back and forth on the dark shadow at her neck. I love the highlight and mid-tone colors meeting eachother, but then the dark tone is just a line with no dither. I think it works especially when you look at how the original photo shading is, but I think if there was a little bit more of a dither transition it may not stand out as being such a different color. But if that messed with how the left part and the middle part of her neck meet, then I'd leave it alone.

The eyes, nose and mouth look great (the parts that display her character/mood/personality). Other than the highlight above her right eye, the shading looks really natural to me. And this is a great example of how dither can work. I completely avoid dither because it always ends up looking like noise to me. This is a great lesson on how to use it effectively.

P.S I just noticed the necklace. Well done. It's got to be hard to convey subtlety with just 4 colors.

These notes are great. Thanks for the insightful feedback. I made an update. I think I could spend more time on the shorts but you're right they at least don't feel like entirely different universes. And I also saw light source problem on his arms after you mentioned it.

I tried to shade his face, but nothing really looked not weird.

Overall I'm much happier with it. Thanks so much!

It's definitely both (not having a better grasp on how light works and fear of over complicating things). This is a huge improvement. Thanks so much for taking the time.

Made some slight improvements. Still feels a little lifeless for some reason.