When Sailor Moon Crystal started airing, there was some commotion over the quality of the animation. While some fans were very happy to see the return of Sailor Moon, not everyone was happy with what they perceived to be low-quality visuals. But now that Sailor Moon Crystal has started to release on Blu-Ray, Sailor Moon has changed yet again.
The practice, which we've covered before, is not unusual. As our own Brian Ashcraft notes in his round-up here, DVD or blu-ray releases can sometimes have scenes or characters tweaked or redrawn. It's a practice done to make the anime better, and in doing so, increase the likelihood someone would buy the new release.
Website Crystal Comparisons's Fred Francis has been meticulously logging the changes between the original Sailor Moon Crystal broadcast, and the Sailor Moon Crystal release on Blu-ray. If you'd like a the quick version, this single image sums up the nature of the tweaks:
The Usagi on the left is what she looked like on the TV broadcast. The Usagi on the right is what she looks like in the Blu-ray release. Needless to say, she looks way better on the Blu-ray release—her face shape isn't horrible, her eyes aren't way too big for her head, and the colors are a bit warmer. I like it.
There are more images that can get pretty detailed about the changes. You can see the bulk of them here at this website, but here are a some comparison shots, if you'd like a taste.