From our FAQ: Android installation doesn't work / grey screen. A few android users have reported this kind of problem. the only things that seem to resolve it are rebooting the device, waiting, and/or trying to install again. it's hard for others to figure out android issues because there are so many different devices with different memory and free space. A few recommendations gleaned from other people's troubles:
* You should make sure you are downloading a public release from an official site, not a beta. The official ones are hosted on itch.io or mega.nz (see #announcements channel for specific links). there is special compression applied to videos and images in public android releases which is not applied to beta releases
* You generally need at least 2x the installer size in free space (after you download the installer to your device) to get all the dependencies installed. some people have needed more than that free.
* if you have the option to install the game to an SD card instead of directly to the device, that has worked for some folks
* if you've never installed a ren'py game on the device before, it may take quite a while to install all the dependencies. some folks have reported needing to reboot their device and/or run the installer more than once to get around the grey screen