Amazing
Despite the slightly low quality this is a well rounded animation, and I really don't understand how people don't get the story line.
It's obviously in a time either too far in the past to remember or in the future, perhaps in an alternate universe, and he's being judged for his actions. White which is what he stepped on is probably symbolic of innocence or purity while red is typically symbolic of war and death, which is the door he is forced to go through. Meaning he believes he is innocent, while they disagree, sending him to his death. :P Its really quite simple.