This is looking really good! I'm gonna echoe some of what Roflqu has said, in that I think some more details to the palms of the hands is important. Right now, it can get a little easy to lose track of if we're looking at the front or back of the hand,and the small details like minor palm creases would really help that.
As well, the soft shading on panel 3 really takes away from the shot there. This feels like its meant to be a very dramatic look, and the positioning of the shadows works great for it, but by softening them when you've got the rest of the comic cel-shaded really takes away from the impact of the panel. It'll sound cheesy to say, but I guess it "softens" the blow. As well, the soft black to white gradient on your sound effects, (The KER SMASH) does a similar thing, softening it a bit much. With how you're going for a big and bold sound effect, don't be afraid to go all in. It's framed well on the panel, so a solid color would suit it much better, and maintain that strong sense of action.
Aside from that, I really dig what you've got here, and really look forward to seeing more whenever you have time!
einsam
Colbitzer
@ 3:32 PM Apr 17th