Successfully complete the game under any difficulty setting. When you play that same difficulty again, you will retain your previously obtained weapons, items and upgrades. The enemies in New Game Plus mode will have an increased difficulty.

"Model Viewer" option
Successfully complete the game.

50,000 Green Gel
Successfully complete the game.

Automatic handgun
Complete the game with a full archive.

Brass knuckles
Successfully complete the game under the Nightmare difficulty setting.

Burst handgun
Successfully complete the game under the Nightmare difficulty setting.

High-Powered sniper rifle
Collect all map fragments.

Machine gun
Successfully complete the game.

Nightmare and AKUMA difficulties
Successfully complete the game.

Rocket launcher
Successfully complete the game.