Why, these are magnificent and fill my heart with such joy, sweetheart! You certainly are a talented one, and I suggest you keep drawing these to improve more and more and I'm certain you would be good with other art styles, as well. Now then, let me finally cruelly criticize your drawings.
I'm joking, but anyways:
'Cosmos Sea' Neptune: This is good. Neptune's hair is drawn very well and her fuku looks good, too. I like the way that you have tried to keep it as much manga-style-looking as possible, and the detailing in her fuku is well done. I egotistically would like this, but I believe it would look a bit better without the teal cape. It looks good, nevertheless, but it does seem a little bit unfitting. Her left hand is drawn a bit oddly and you could work a bit more with her eyes. Anyways, this is overall a good picture and the few mistakes I mentioned don't take away much from it.
Act 1 - Cosmos 1: This one could be a bit better. Hotaru is drawn well, though it would look better if her hair was made more apparent and the background coloring is good, the different shades contrast well with one another. Chibiusa is yet again the poor little unfavored one for moi, though. Her body is drawn well and so is her dress, but the coloring is not that good. I don't really like it how you have used a darker pink on her head, then a lighter one on her pigtails, which doesn't make a good contrast and makes it seem very thin. The same goes for her dress, that has darker shades in some parts, and I'm especially not very fond of the ones that seem to intertwine with her dress. I believe coloring it light pink or salmon pink would be fine. Her eyes need a bit more work, too. Overall, this is fine, though I cruelly won't tell that I like it much.
Goddess of the Sea: This one is probably my favorite. There are very few flaws in this one, and this is probably you at your best. I adore Michiru's dress being formed of ways, and the colors you picked for it contrast one another very well. The aspect of her being surrounded by waves, as well, looks very good. Her hair is drawn incredibly and her face and expression, give a very tragically beautiful aura. Anyways, this is a highly elegant and sophisticated drawing.
Red Blossom: I like this one. Rei is drawn well, and her expression gives a very calming vibe. The dress detailing is well done, too. The cherry blossom branches look a bit odd, though and misplaced. I like it as an idea to draw in a cherry blossom scenery, but you could have drawn them in some other form.
Turbulent Wind: Ah, this is certainly my second favorite. Dear, dear Haruka is drawn very well and her expression and pose while holding her Space Sword capture her essence and persona well. I adore the way you have used lighter coloring in the lower parts of her dress and the way you have drawn it around her, truly makes her look like she's being embraced by the wind. Overall, this is a drawing with very few flaws and it gives off a rebellious yet very charming and elegant aura.
And that's subjective about liking Usagi and Michiru.
I kid, but anyways:
Serene White: This one is fine. Neo Queen Serenity, if I'm not mistaken, is drawn pretty good. I like the dress you have picked and you have drawn its' detailing very well. Though I wish it wasn't so loose, and it was a bit smaller, since it would look very good.
Nights by the Sea: This is highly artistic. You have drawn Michiru very well, her hair coloring looks incredible and I like the pale blue coloring you have used in the background, as well. Her lingerie is drawn well, too.I like her expression, it gives her a mysterious and intriguing vibe. I also like how you have photographed it while drawing on your desk, with your other art tools around, it does look very artsy.
Teenage Superstar: This is a pretty one. You have drawn Minako very well, with her hair coloring being especially good and the background is incredibly well done. The outfit you have picked for her gives off a very teenage vibe and it's pretty fitting to dear Minako's personality. Overall, this looks a bit like a photo shoot and captures Minako's essence well.