This is Usagi from the very beginning of the series. Manga act 1, to be precise; at this point, I believe that she's remembering that there's a jewelry sale at Osa-P. At this point, keep in mind that Takeuchi-san is just beginning to portray our heroine, and her features aren't really set in stone. Note the size of her odango, and the cut of her bangs. I find the portrayal of the eyes particularly interesting. (Besides, you can't miss them. They take up half the face.) Note the length of the top eyelash stripe; it's pretty short, doesn't arch too much, and barely manages to convey the rest of the eye's shape. The round, wide eye conveys excitement.

This is Usagi at the beginning of the Infinity arc. Mark the lengthening of the top eyelash stripe; it now curves over a lot of the eye and conveys the eye's shape much more clearly than before. Note the much larger odango, with the different winding pattern. She probably hasn't gotten a haircut since tankoubon 1, and just wound more hair into the buns. Also, you'll see that she grew her bangs out a little more; they're not in such tight curls any more. Takeuchi-san is using shadow on the neck to emphasize the shape of the jaw. (Usagi's getting depth! <grin>) Through the first couple of acts, Takeuchi-san didn't use much shadow; however, as the series progresses, her use of shadow becomes more prevalent and beautiful.

This is act 38, and they're fighting the Dead Moon; Sailormoon has just heard a lot of sobering information from Elios, which is why she's got that tragic look on her face. See the detail of the shadows across the face and forehead? There are even shadows for each separate hank of hair. While we're talking about the hair, notice the bangs; they're now really long and much floppier than before. Usagi-chan, when was the last time you got your bangs cut? I suppose being a senshi of justice takes up a lot of your time... The eyes are following a definite trend too. The shape of the eyeball is now egg-like; the bottom is relatively larger, while the top tapers to a rounded point instead of being the oval that it is at the beginning.

Here, Sailormoon is fighting Galaxia one-on-one in act 51; this accounts for the battle-ready expression and the angrily slanting eyebrows. Note the huge contrast between light and dark on her face; volume 18, the climax of the series, does a great deal with shadow. Also, her bangs are even longer, and (as would be expected in the middle of a fight) in disarray. The egg-shape eyeball that I mentioned in the previous example is even more evident here; in fact, you'll see that the arch of the top eyelash stripe accentuates its shape. The curve of the top eyelash stripe is much more severe, clearly emphasizing the shape of the eye. This makes the eye much more serious and beautiful (in my opinion); when Usagi opens these eyes wide, she doesn't look at all childish.