Do not download "premium" emulators. The official PPSSPP is free.
Note: As of my current knowledge, "Naruto Shippuden: Ultimate Ninja Impact 2" does not officially exist. Bandai Namco released only one "Ultimate Ninja Impact" for the PSP. This article explains that reality, covers the original game, and guides users on downloading and playing the actual title via PPSSPP, as most searches for "Impact 2" are looking for a sequel or a patched/fan-modified version. Do not download "premium" emulators
Naruto Shippuden: Ultimate Ninja Impact 2 PPSSPP Download Guide covers the original game