Press the green flag TWICE and turn on Turbo Mode for best results. The "secret ending" to BotW is acquired by defeating all Divine Beasts and getting all of the memories.
Thanks to the guy whose sheet music I borrowed. You can find them here: https://musescore.com/user/7428766/scores/5293778 Also, thanks to Manaka Kataoka, Yasuaki Iwata, and Hajime Wakai for composing this.
