Did you play through all the scenes in-game?
If not you should unlock the gallery in the settings. We just checked v0.30.2.2 and all 3 Big Melon scenes are available in the Gallery.
I pressed go to latest content
Did you buy the skins from Reina and play through them? If you don't want to do that but want to see the scenes — unlock the gallery at the bottom of the settings menu!
