A sad story with a violent twist
Your validation for the spiders actions okay but most stories that end like this have the main character disappointed in his actions. We see no remorse in the main character at all. He is not even left lonely.
The animation of his anger is well chosen with a frame by frame feel you style of the emotion of anger verses his somber beginning are well contrast. We have no question the main character is no longer the sweet meloncoly character we thought you introduced us too. Your techniques are mature and enlightning but the ending shies from reality and the character you first introduced us too. That's my opinion but you are the director.
Overall very nice work.