Thanks so much for all of the great work! I now use my 3DS as my dedicated anime watching machine!
I'd like to suggest 2 minor improvements:
1.) Full Screen is awesome. I'd recommend making it so that the "A" button that is used to pause/unpause the video does not exit fullscreen. I think just having Select and the touch screen exit full screen is enough. Also, I think that the "press any button to exit fullscreen" message could be removed and placed under controls - or just display once.
2.) I know I said this one earlier, but I think it goes better in this post as it is a small quality-of-life update: Maybe ZL/ZR on New 3DS or D-Pad/Circle-Pad on Old 3DS could be made into a 3-seconds-forward/3-seconds-backward control. This would make it really easy to go back and forth small amounts, with the touch screen being used for seeking through the video by large amounts.
Again, thanks for the great homebrew! Keep it up!