The PS4 remaster is a significant technical jump from the original PS3 release, and the "Fix" files aim to preserve this performance:
The game started. But not the usual title screen. Kratos stood on the cliffs overlooking Athens, but the sky was wrong—a deep, bruised purple, like sunset after a wildfire. The HUD was gone. So were the tutorials. God Of War 3 Remastered Ps4 Pkg Fix
Players have reported various issues with the God of War 3 Remastered PS4 PKG file, including: The PS4 remaster is a significant technical jump