Japanese Halo fans are not happy. For a decade, the roles of Master Chief and Cortana have been voiced by Atsuki Tani and Akiko Koike, but for Halo 4, the pair have been replaced by Rikiya Koyama and Ayumi Fujimura.
Changing the voice of a man with no face is pretty drastic, so you can understand why fans are upset.
I can't quite understand how this demonstration was going to work though. CLimbing Mt Fuji in costume and holding up a note that can't even be seen on film must be #15359381278 on the list of effective means of protesting video game changes.