What version did you download? There's no option to switch to Russian.
I see what you mean, the new version I updated now is fixed, but not if you already did that. In order to make it work you'd have to delete ALL DATA and caché of Renpy from your computer before downloading it again. That, or trying to click on the part where the preference button was. It's tedious, but it can be done. I'm so sorry for the inconvenience. I'll try to find a better solution in the meantime.