Installation guide
How to Install APK Files Safely on Android
What an APK file is, how to check it before installing, and how to manage the "install unknown apps" permission on Android.
An APK is the package format Android uses to install apps. Games you get from an app store are delivered as APKs behind the scenes; downloading one directly just means you handle that step yourself.
Check the source first
Only download APK files from the developer's official website or from a page that links to the developer's own files. On the JZ666 page, the download button takes you to the JZ666 website.
Allow installation only when you need it
Android blocks installs from outside the Play Store by default. When you open an APK, Android asks you to allow the app you downloaded it with, usually your browser. After installing, you can switch the permission off again in Settings → Apps → Special app access → Install unknown apps.
Keep Play Protect on
Google Play Protect scans apps on your device, including ones you install yourself. Leave it enabled.
Updating a game you installed manually
Download the newer APK and install it over the existing app. Your progress stays, as long as the new file comes from the same developer.