A: Fem Shep
Here are some really early pixel artworks I did in a few hours. More to come :)

Kratos.gif
32 x 32 - 326B

fem shep.gif
64 x 64 - 615B
Comments
If you want feedback: is it possible to eliminate some of the perfectly straight lines in your images (femshep's right leg and jaw, Kratos' arms)? Or is dis sum style thing which you'd prefer to stick to?
Kratos' front arm might be a bit long?
Looking forward to the more to come!
Like: Cool proportions, love the omni-tool :) Good overall
Crit: Kratos' arm - I thought it was a gun or a blade. Maybe he need a blade more than a long arm there :) Also FemShep's left leg is a bit bent where the knees are - and the texturing is a bit too even all over it making it seem flat.
Keep it up :D
one thing for me that's hurting the maximum appeal in both, is the arms seem to get lost in the body. Something you could try is changing the silhouette so the arms read clearly, or have different value on the arms than the body so you can distinguish the arms from chest area.
As Seen in the C.Viper image attached, the pose is very similar, but it reads better because the arm inside the body is silhouetted against the white of the t-shirt.
In your sprite you have the white and red stripe down the arm which kinda helps but the shades of grey are too similar to tell body and arm apart, you could make them thicker to help it more or looking at other street fighter stuff, an easy fix ( but less Mass Effect Style) could be to have sleeveless shirt.
Really good job on the dithering on the left thigh, and shape on her right shoulder pad, looks awesome!
I feel the stance has become too stretched - as in the hind legs wouldn't look like that in a combat-ready stance - they'd be flexed a bit :)
Cammy's doesn't actually fit (did a search), since her front leg's turned inwards - but let's use C.Viper from above: her back leg starts more vertically down, then bends out. That little bend makes the stance more dynamic, like the fighter is ready to jump - this version of Femshep has a very wide stance, which doesn't make sense in a real fight as she'll really struggle to move from that stance.
PS. Cammy's stance still works even if her front leg's straight cos her back leg is bent, so there's still that flexibility :)