This looks to be rather promising, as a pilot I noticed it was six and a half minutes. How long do episodes plan to be?
The animation was very smooth. I enjoyed the backgrounds since it gives a nice background while the characters look slightly more cartoonish in design. The anime-esque behavior of the characters and how they were drawn though looks great. The swirly eyes and usual anime looks were quite nice. If anything, the only thing that seemed a little off in animation was when NINJA's eyes were swirled, his one cheek had the lines, while the other one did not which made me think his one eye might have been erased by error for a moment instead of it just being his cheek swelling a tad bit.
The background music was atmospheric and set the mood for the moment. The slight scare chord as NINJA suddenly noticed the #1 ninja (Gardner) giggle a bit was odd. It gave the feeling Gardner was going to attack him for a moment rather than inform him of the quest (Gardner most likely set up) leading him towards where the final match will be set.
The narrator voice left me with a question at the start though. Did Gardner become corrupted by the Wristband or was he already that way before obtaining it? Either way, him turning into a flower plant to seem invisible after giving NINJA the gem was funny.
Overall, this looks quite promising.