All of these characters are truly unique! You may have noticed with the older fellow and the couple muscle guys but I was thinking its just a couple in the greater collection - nope they all tactfully fit a general model and scale but with a variety of modular in nature yet not cookie cutter aspects - each character has subtle differences in shades or placements which when thoroughly observed (easiest at pixel scale, I liked 500% for editing) seem to deliberately convey the characters demeanor and tell you more about them - with such a small touch it's actually incredible.
To give reference- take Chars 035 & 036 and the middle frames from rows 1 & 2 (frames 2&5). (non combat sheets, from folder 24x48)
The 1 pixel difference from thighs into back in 036's posture has her hips thrust forward while 035 is standing straight with a very poised demeanor, complemented by the heels she's wearing represented through the pixel width of the feet when shown front facing and the ratio of pixels for toes and heels in any side facing stepping frame where the additional pixel in the toes portrays heels on 035 and by moving that 1 pixel to the heel on 036 they change to boots. It goes even further though, the one pixel difference in foot length from frame 5 (left facing idle) along with 1 pixel difference in knee protrusion and joint posturing (035s legs are taught behind the knee while 036's are relaxed-slightly bent) even further convey this. This focus on posture is highlighted again in the 1 pixel difference between chin and shoulder gaps In this comparison I think posture is the biggest focus in the contrast of demeanors. Likewise shading used in the arms and skirt on 036 adds contouring to the limbs which with 035 is instead used to draw contrast between waist and chest. I'm sure there's more I missed and you can see many more variations and examples pulling up any of the other characters but I was thoroughly impressed when I jumped in to edit, so much so I decided to come write this review. Apology to those bothered by walls of text.
As someone just beginning their journey into the craft of pixel art I appreciate both the great design of characters offered in this set, and just as much the imparted lesson of how the tiniest details can translate to such a large impact in the full piece.