I've been working for two days on this, and I finally did it. This is the ending I'm going to use for my upcoming Super Mario Bros. Z continuation, Super Mario Bros. Z: resRXion. It pretty much got its inspiration from the second ending to Fullmetal Alchemist: Brotherhood, and like said ending, it is set to "Let It Out" by Miho Fukuhara. I'm sure someone will do a comparison video with footage from this and the aforementioned FMA:Brotherhood ending.
Prior to making this ending, I was having a hard time thinking what I'd use for the end theme for episodes 1-4. First, I thought about "Genkai Battle" by JAM Project, then, "Drastic My Soul" by Mikio Sakai, until I found "Let It Out", and what a successful find.
Sprite credits are described in the video.
Anime Studio Pro 11
Sony Movie Studio
Note: Super Mario Bros. is copyright of Shigeru Miyamoto and Nintendo. Pokémon is copyright of Satoshi Tajiri, Ken Sugimori, Game Freak and Nintendo. Dragon Ball is copyright of Akira Toriyama and Shonen Jump. Sonic the Hedgehog is copyright of Naoto Oshima and SEGA. Family Guy is copyright of Seth MacFarlane and FOX. Super Mario Bros. Z is copyright of Mark "Alvin-Earthworm" Haynes.
Second note: In the minute mark, I have added another character to the continuation's plot. Here's a hint: This character has conquered and destroyed many planets, and drove a warrior race to near-extinction, leaving only a few survivors.