I'm pretty impressed by what you accomplished without reference. I like the loose gesture aspect of your sketchwork. The poses are fluid and unified, not to mention you've got a pretty good handle on proportion. Comic book muscles always blow me away, and I'm too inexperienced to offer crit, but they look awesome to me XD. The only thing I can think of is maybe on the girl on the second page with her hands on her beltloops. Maybe tilt the torso or thrust her hip out a little more to make it more dynamic? Your posework alreaddy makes a nice statement, but tweaks and exaggeration can help make a bigger impact especially when it comes to comics.
The kactaur made me lol a bit XD