doesn't look good.
in my opinion the whole icon would be a LOT better if it's rotared so that the knife and arm strike in a steep diagonal.
do that asap
EDIT: Blood looks like some pink rubber
There are other stabbing icons that have already done that angle. Specifically, "Backstab" and "Sacrifice". I chose to do a vertical angle because of that reason.
Make blood a bit more realistic, and make the dagger hit something, like a part of body(chest) now it looks like stabbing a border
A lot of the quality on the blood was destroyed when re-sized the image to 64x64. Sorry. Also, adding a part of the body being stabbed would really limit this icon's uses, I think. Suppose you wanted to use this icon for a "Cut Throat" or "Back Stab" ability. You could, because there is no definite thing being stab. All you see in the Icon is that whatever is being attacked is bleeding like a stuck pig, which opens up a world of possibilities for the user of the icon.
Those things above, and a background would be cool.
I considered a background, but thought it would distract to much attention away from the blood, which I wanted to be the main part of this icon.
It just looks like your hitting something which instead of blood has chewing gum. Also the angle of the hand is unrealistic. You wouldn't stab someone vertically like that while keeping your hand straight. There just has to be some bend in the arm. Also it really needs a background, I mean a simple gradient would do if you're out of ideas.
The angle of the hand is very realistic. The original sketch I did has the full arm bent back at the elbow to form a 90 degree angle, which is what you mentioned here in your post. Most of the arm just had to be cut out from the icon. No where in this icon is it implied that the arm is kept straight. It is just unseen.
And to everyone asking me to change the blood, please listen; I will change it because so many people want me to. But please try to understand. I wanted to create something original here. Maybe not what's presented in the icon but the execution of it. I wanted the angle and blood to be different from any other previous icon created. All the other kinds of blood gushes had been done before. I could have simply put a mess of the stuff spurting from the point of impact. But instead, I created a "Splat" blood spew, because I wanted to be unique. I'm sorry if the idea was not taken well. I'll change it to something more conventional.