So the original gallery unlocker doesn't work, i read in another comment that you can change a few lines the script videoGallery.rpy to do that.
I'm on version 0.9.5, and I managed to get the gallery to show me all scenes by changing the following line:
Line 507: return getattr(persistent, self.lockCondition, False)
Replace it with this:
Line 507: return True
Strictly speaking it doesn't
unlock all scenes, but the effect is the same, you open the gallery and you can watch any scene you want.
Here's an image:
View attachment 3867924