The foreshortening is ridiculously disproportionate on the anxious character with the blue hair. Her head is too large, and her arms, particularly her right, is too short and appears to be in a state of perpetual foreshortened appearance where it should have come closer to the viewer.
These errors are only further emphasized when compared to the other characters, as except for the distressed blue haired girl, everyone else is drawn in a proportionate fashion.
This is one of those pieces I can't stop staring at, as new details keep catching my eye. The outfits, the poses, the background… the characters expressions, too, grab my attention, especially the girl at the bottom. I keep wondering what she's looking at, and why she looks so surprised.