Instructions
Defeat the game on any difficulty to unlock the "Spud of War" costume. The costume is exactly what is sounds like: Kratos wears a bulbous potato costume throughout the game when wearing "Spud of War." For help beating the game, consult the game guide in Resources.
Complete all of the Challenges of Hades to unlock the McKratos costume. The Challenges of Hades are unlocked after defeating the game. There are five challenges in total; consult the "Resources" section on this page for a guide to beating each of them. The McKratos costume places Kratos in a kilt throughout his adventure.
Unlock the Mime of War costume by defeating the game on God Mode. God Mode is unlocked after all five Challenges of Hades are completed. God Mode is extremely difficult, because enemy attacks will deal extreme levels of damage to Kratos. The Mime of War costume leaves Kratos resembling a mime in subsequent playthroughs.