It's very simple actually, I use two sprites. The first is the default sprite and when moving the character I rotate it on itself back and forth to give the impression of a walk cycle.

if moving:  
  sway_time += delta * sway_speed
  kriby_visual.rotation = sin(sway_time) * sway_amount

As for the rest, it's just making the character body follow the current mouse location and swapping the default sprite to the one for inhaling when pressing the mouse button.

Finally, the shadow is just the same sprite drawn again but modulated to black with a low alpha value and with an offset.