A wonderful way of thinking
I love this piece for the humour and for the fact that the logic is something that you can barely argue with. The introduction was funny, if a little crude, talking about how everything for this piece was either begged, borrowed or stolen, enabling you to make such savings and pass them on to the consumer.
With some of the points that you make for the actual logic, I would like to bring the following to your attention:
1) The human bladder is much like a balloon - while strong enough to contain itself, it will grow and shrink with direct correlation to the amount of fluid contained within. Have you considered kidney stones could be causing such a blockage. How did it go with your doctor?
2) Ninja Powers = The One. I love this concept, though you should surely have considered that there is one more thing to consider about Ninjas - they are invisible against a black screen. Perhaps consider telling us all that since the ninjas could not be seen, you have painted them in bright colours, to make them instantly recognisable.
3) Cowboys. One thing greater than cowboys would be Chuck Norris, since he owns most things internet. Perhaps a little aside there would have just dragged this on a little further for even more laughs. Say 40 / 30 / 17 / 13, perhaps?
With regards to the animation, I would suggest that you do something to work on the background around the characters - I clearly saw the boxes around everything, which was a shame - you've got some good animation techniques, it would be a shame to spoil them with something like that.
[Review Request Club]