To understand the Google Play Store of the Android 4.0.4 era, one must first contextualize the operating system itself. Released in late 2011, Android 4.0 (Ice Cream Sandwich) was arguably the most significant release in Android history. It unified the divergent codebases of the tablet-only Honeycomb (3.0) and the smartphone-centric Gingerbread (2.3).
: Go to Settings > Security and check Unknown Sources to allow installation of APK files outside the Play Store. Android 4.0.4 Play Store