Here's some constructive critism (hopefully I won't be TOO mean :P)
I can see that your style is a very Sonicy/SEGA feel to it.
First off, try to work on the structure of the head, the heads all seem to be chopped off in the top and back
Secondly, the legs seem fused together, you have to think of real life. Would a person be able to stand that way or not? For full body poses, I like to position one leg sideways and the other leg somewhat foreshortening towards us (depending on where the chest would be) I prefer angled (or 3/4) body posture
I do like the chest anatomy of the fox person, I myself have a hard time with partial body armor like that, usually I do robot/knight armor. The chest plates are very nice as well
I like your simple color scheme also on said fox, it works very nicely.
Try to work on that tail, it really looks to skinny for a Fox tail, I make mine very big and fluffy (gosh I wish I had my pics so I could show what I mean >.< )
All in all, it's nice, but try and work harder on anatomy, don't worry, everyone (even myself) has a hard time with anatomy (my hard times are hands, feet, and pretty much most of the female anatomy X3 )
Keep on praticing and try to learn from other artists. Remeber, don't try and STEAL their style, but observe it instead.
Here are my fav artisits:
http://andrewdickman.deviantart.com/
http://traditionaldanimatio.deviantart.com/
http://bluewolf487.deviantart.com/
http://galadrex.deviantart.com/
Enjoy, and never give up