Hold L1, L2, L3, Circle, and Square simultaneously before the "Sony Computer Entertainment Presents" screen appears. The letters will turn purple if successful.
Additional codes from Scribd allow for gameplay changes like L1 + Left for slow motion and L1 + Up for high speed. God of War 2 Cheat Codes Guide | PDF - Scribd God Of War 2 Ps2 Codebreaker Codes