Tom Clancy's Rainbow Six: Lockdown

This process affects a critical game file. Carry on at your own risk.

Go to Rainbow Six Lockdown\data\save file then open the lockdown.pro in Notepad and you''ll see the levels to unlock under mission data like completedNormal = "0" and completedChallenge = "0". Set all the zeroes to "1" to unlock the stages as needed.