Defeat Andrei in level 1, and do not brainjack Goulnaba in level 2.
Go left on the train tracks in the Lyon level, talk with Badelaire and brainjack him.
Brainjack Goulnaba in level 2.
Enter the bazooka room in the Hong Kong level. Go up the stairs to the left and brainjack Lee Fei Shan.
Successfully complete the Vienna level with Rumrod. Use the panel and defeat Marguerite.
Brainjack Rumrod in the sewer area of the Amsterdam level.
Successfully complete the London level with Badelaire, then brainjack Sam in the tower.
Successfully complete the Taj Mahal level with Lee Fei Shan, use her memory to enter Shaja's room, then defeat him.
Defeat Youthfu in the Mecca level.