Absolutely love the color palette, and the steamy, dreamy effect.

This is gorgeous. The animation's so smooth.

I agree. The dragon's solid, and I kind of wonder if it'd be a stronger piece with the dragon as a standalone.

Let's start with what's working for Bubblegum here.

• The hat is excellent, needs 0 work
• The collar and sleeves of her shirt work
• Her waist, arms, and hands look good
• The rifle's missing the hand part, but still works excellently aesthetically
• The legs themselves and stockings look good

As for things that are throwing me off:

• Her hair looks kind of like spaghetti that's been painted at the ends - it clumps together like a mop, and I suspect this is because of 1. a general flat contrast when (especially bleach) blonde hair tends to highlight on edges and ends and go dark between valleys (example: https://media-cldnry.s-nbcnews.com/image/upload/newscms/2016_19/1084171/summer-hair-color-today-160511-tease.jpg ); you've got some of that going on with the pink, but I'd darken the darkest hue on the pink, too
• Continuing on the hair - there's some style inconsistency in the level of colors it has (4 colors vs 3 on areas that take up more space and attention), and I think you could toss out Shade 2 on the pink with only improvement (I'd say tossing out Shade 3 on the stockings and trading it for the knee shade would make similar improvment, too)
• The breasts received too much shading focus for what they're probably actually doing: I'd nix the wrinkles in the middle and just leave her left as it is
• I don't know for certain if the shirt drooping back would make more visual sense if the breasts were simplified, but I suspect it wouldn't; if I were you, I'd hitch it up to where the second gray shade starts on her right bottom side of it and sharpen the edges of the shirt to communicate t-shirt/dress shirt rather than sweater heaviness in the material
• For the skirt ... I'd clean up the lines, a lot - straight, no wobbling, for the kind of material a pleated skirt is likely to have; I like what you did with her right edge of it, but I'd firm up the left side at the "band" by having it more straight/up and down than the lower
• I'd get rid of that garter entirely, or thicken up the top from our middle-left onward to match consistency with the rest of it; there's various shading choices you could make from there, but as it is it just looks unfinished
• There's a stray dragon pixel to our left that's just kind of driving me crazy
• The face is hard to say because the hair looks so thick it kind of puts the shape of her head in question; the eye patch doesn't really look functional or stylistically appealing either - I'd make it bigger, strappier, or nix it and fix the eye under it
• I think the shoes work fine as they are since they're not a major focus of the picture, and I really like what you did with the tops of the stockings to emphasize their conformity to her legs
• I like the way you signed and the simplistic lines, but the + signs in the upper right take away from the coherence of the design