If you mean the first-person puzzle game where you swap between two parallel dimensions (light/dark or matter/antimatter):
You will need to shift between these dimensions to bypass obstacles that are impassable in one form but traversable in another. duality game walkthrough
(reduces integrity by 2) to lower firewalls, but be careful: if a server's integrity reaches 0, it disappears and can fail the mission. If you mean the first-person puzzle game where
: Locate symbols on the ground in the normal realm. Enter the Nightmare Realm, kill the corresponding Standard Bearers, and return to the normal world to plant the symbols. Final Boss: Princess Caiatl kill the corresponding Standard Bearers