The rearview kneel his legs are a bit squishy, in that they get shorter and thicker without showing that they're bending. Also, I'd expect we'd see more of his heel in the last frame.
The one facing away from us between the battle stances, I'm not entirely sure what its meant to be... Is it climbing? If so, his arms should be moving more up and down, rather than side to side. Also, his head should move.
The four swimming ones, I'd maybe want to see them bob up and down by one pixel every other frame.
For the Jump in the sideview, I'd want one frame of anticipation. That is one frame where he crouches before jumping. Also, when he lands, there should be a frame where his knees bend before he stands upright. The same should apply to the front view as well.
Its great work tho, and I look forward to seeing updates.
