Trully an amazing piece! You've captured a great scene that is not too crowed and cluttered.
The scene definitely tells an imaginative story, with characters interacting with each other not just 'placed' in the spaces to fill gaps.
The colours (although obviously taken from the original characters) compliment each other wonderfully and you have a right amount of 'whites' spaces to let your eye wonder around the piece without being confused.
For originality, I have given a 4, as although this piece is absolutely amazing, there has been others like this (whether that be about games or not) and as the character are not your own. But with that said, you've captured the styles of each of the characters very well with all of them being completely recognisable, but I can still tell you have added your own twist/spin on each of the styles to make this piece very unique.
Overall, this is an amazing fanart!