The castle is awesum shit, just make the blocks that stick up on top that is facing us a little "thicker". i know that this kind of angle is kinda hard but right now they look paper thin. also the shade of grey used to outline the bricks in front should perhaps be a bit darker so that the texture is similary strong in the shadows as in the light. but that might just be my monitor.
beetle is kinda flat. i guess the white dittering is meant to be a highlight to show form but it doesnt read well. Also the collors are standard mspaint which generally is a bad thing. I'm not good at animation so no comments on the third.
gj and welcome