Installing a game that uses APK and OBB files is slightly different than installing from the Play Store. Follow these steps carefully to avoid "Download failed" errors or black screens.
Download Project IGI APK + OBB File (Patched for Android) – Full Setup Guide
Because the game was never natively coded for touchscreens, the version is the real hero here. The vanilla PC-to-Android ports were unplayable. The patched mod does three critical things: