If you have a legitimate backup:

When Sony first showed the Killzone 2 E3 2005 trailer, many accused it of being pre-rendered CGI. Guerrilla Games spent the next four years proving it was real-time. The final game used deferred rendering, dynamic lighting, extensive particle effects, and motion blur to create a chaotic, lived-in warzone. Even today, the game’s lighting and post-processing hold up remarkably well.

The PKG (PlayStation Package) file is essentially a digital version of the game, allowing you to download and install it directly onto your PlayStation console.