ok, so first of all, I don't recommend doing your own sound effects, and the whole entire intro was tedious and boring to me, although I assume it was supposed to be humorous >.> your overall animation is a bit choppy, try putting in more in-between frames and maybe using a higher fps. Another thing I noticed is that parts of them would be left after they move, and I can't honestly think of a reason for that, but I would recommend using a different layer for each new "thing" in the animation, or at least erasing what doesn't belong. And why does the grey dude occasionally spawn more arms ._. I don't quite understand that..