The way the faces are animated is top notch, epsecially the goon with the knife. Very fluid, lots of motion, and very expressive.
I suggest not skimping on the animation in a few areas.
-The flying fist at the beginning is just the same image being expanded. If you gave it some directional lines it would give it the illusion of actually moving. Or draw more detail marks and shading as it gets closer to the viewer.
-Like when one of the goons is crying, you stretched and expand/contracted his shape with the transform tool. It feels out of place when you did that because of how fluid the rest of the animation is.
-When the goon initially starts crying, you just used the same sequence of his mouth opening and closing. A little bit of variation in the animation goes along way.
Of course I understand animating every single scene is time consuming, but ultimately the finished product will look much better.