Welcome to icon crafting
First of all, I'd like to point out of the awesome concept you've got there. The Hive really does need more stealth walk icons.
You've stricken a bulls-eye with replicating Blizzard style, two pastel colors yet they are from opposite sides of a color circle, and by applying cartoon-ish feel to the icon.
But, even thought you got it right in some aspects, you missed to represent shadows and light sources.
Every icon should have at least one light source, and a set of shadows to follow it. It gives it the realistic feeling of making it 3D, rather than using only base color to represent an object, or in this case, foot. You'll find some tutorials on basics of shading at the end of my post, to get you started and introduced
Also, personally, I'd like to see a little bit more of distance in here - by making more of the foot visible by shrinking it a little. I feel it would give a better projection and impression of stealth.
One thing again, I'd also love to see a slight glow around feet with color a little lighter that the background, as it would help the contrast come clearer, and your foot a lot more eye catching.
Hope I haven't killed you with the wall of text
Looking forward to updates!
Some tutorials you might find useful:
http://www.hiveworkshop.com/forums/2d-art-tutorials-281/basic-icon-guide-166366/
http://www.hiveworkshop.com/forums/2d-art-tutorials-281/general-icon-process-tutorial-243593/
http://www.hiveworkshop.com/forums/2d-art-tutorials-281/icons-crazyrussian-93857/