it does not ask for "full control" of your phone LMAO large games can't always be packed into a single apk, so android ports of larger renpy games often distribute the apk and the game's files separately. the phone is asking for access to the location where the game's data is stored in order to load the images, audio, video, etc. it's not easy to get games designed for pc with thousands and thousands of images to work on a very broad range of mobile devices, and this is a pretty normal and efficient way to accomplish it, but i understand if it makes you uncomfortable :]