Enable "Install from Unknown Sources" in your Android settings and install the APK file.

Several developers have created "Lite" versions of the game specifically optimized for mobile hardware. These often include touch controls and compressed assets to ensure they run smoothly on everything from budget phones to high-end flagship devices.

Most APKs feature integrated touch-screen overlays, but they also often support external Bluetooth controllers for a more traditional feel.

Move the OBB folder (often named something like com.l4d2.game ) to the Android > obb directory on your phone's internal storage.

Obtain the necessary APK and OBB (data) files from community sources like PDALife.