I like the sense of motion in this sketch. Something I find really appealing in your art is the fluid shapes and lines you use, and you see a lot of them here. I like the lively, fluid, animated lines that go from the shoulders through the arms on these two -- they're exaggerated just a bit, in it makes the arms feel more alive as they move and settle into the poses they have them in. And the composition is kinda circular, with them revolved around each other in the oval shape, and the curvy, fluid lines you use helps to imply that sense of motion nicely, too.
I really like their hair! You can feel it being pulled about in an interesting, lifelike way. The top figure's hair falls down, being pulled by gravity since they're hanging upside down -- and it looks great. Though the other figure's hair is really exciting -- I love the shapes of her hair, how it's flying in front of their face like that.
I also thing the top figure's hand, the one that's outstretched, looks really well drawn.
The mood of this pic is interesting. There's this kind of quiet, muted emotion on the characters -- maybe some quiet pain or melancholy, with the one reaching out desperately towards the other, and the other seeming distraught with hands clasped in front of her, closing off her body language. There's that quiet, but intense mood, coupled with the very active sense of motion of their hair, of them floating around in an implied circle, of the one figure reaching out so forcefully. It all has a really interesting effect and feel.