Package name editing

The package name of the game should be modified so that it doesn't conflict with the unmodified game version.

Android

With decoded resources

If you decoded resources when extracting the APK, then you can just modify the AndroidManifest.xml file with a text editor.

You should modify the package attribute as part of the top level <manifest> tag.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="package.name.here" >
    ...
</manifest>