Spider-Man isn't a difficult game to complete even on a harder difficulty.
This way you get all the advantages of your completed save - XP level, unlocked skills, suits, mods, gadgets - to help you adjust quickly to the new difficulty. Seeing as this trophy comes with an update that also requires you to finish a New Game + play through you might as well combine your efforts and set your New Game + to Ultimate. You must not change the difficulty at any time during your play through of the main story. To unlock the Power and Responsibility trophy in Spider-Man you must complete the main story of the game using the new hardest difficulty 'Ultimate' added in Update 1.08.
