Gallery Mode contains no gameplay spoilers until you have naturally reached that point in the story. Locked items are shown as silhouettes with a brief hint on how to obtain them.
This is a game-changer. The new mode includes 3D dioramas of key locations (The Hidden Leaf Village, The Cursed Temple, The Iron Fortress). You can explore these environments without combat pressure, looking for hidden easter eggs that hint at future DLC. shinobi girl gallery mode new