Mr. Blonde's Revenge is unlocked by completing all solo missions in Agent difficulty or higher.

Maian SOS is unlocked by completing all solo missions in Special Agent difficulty or higher.

WAR! is unlocked by completing all solo missions in Perfect Agent difficulty.

Duel is unlocked by finding all weapons in the solo missions and gaining at least a Bronze rating on each weapon at the Carrington Institute Firing Range.

Unlock Perfect Darkness (new difficulty setting) by beating all solo missions in Perfect Agent.