Survive the first level (despite dying).
Finish the prologue.
Complete every mission in the eastern region.
Complete every mission in the western region.
Complete every mission in the northern region.
Make the machine bleed to death.
Enter the factory and live to tell the tale.
Face The Man and walk away victorious.
Complete all the challenges on any level.
Complete 20 challenges.
Complete 40 challenges.
Complete every challenge there is.
Obtain all journal pages.
Complete all the conversations with your companions.