You still there?
Did an edit earlier so I thought I'd throw in some tips which should help.
More than contrast the biggest issue is that the silhouette is too compact:
All it says is that it's a blob guy standing. We don't know what he's doing.
A good silhouette describes the character's actions. It makes a pose THAT much more readable. The smaller the sprite, the more important readability is.
In this instance he's holding a rock up to the player, at a 3/4 angle.
At a sprite this small you only need about 4-12 colors. That depends on the level of detail you want and the res it's going to be seen at, but start with a few that you can block out the major shapes with using a larger brush.
Easier to manage, better workflow.
Then add colors from there.
If the color can't be seen at 1x/at a glance, it doesn't matter or could be handled another way.
Reusing your colors comes down to, this color is similar to the other, so experiment with that color's properties until you find a color that works for both.
Sprite size is also a factor there.
Posting on rocks soon, sorry for the bump/sporadic posting, but right now it's what I can do.