Now im no expert in games and how to make them or anything
But you might have to update the game so this kind of messages dont appear anymore...
Viewing post in KonoSuba The Harem Adventures [v2.3] (NSFW 18+) comments
Thanks for reporting, but the Ren'Py I work with does not provide verified signatures. As an app that does not have a verified Google Play signature, this message appears. That being said, the game was ported for Android by DA, and it is completely safe. Most VN games you will download will show this warning.