[ ] Add a special item that allows to take a "photo" from each type of enemy (only once). It can be sold in some shop, or found after completing some sidequest or trading quest. The item can be a "camera", or even better, a "soul catcher" that throws some kind of "projectile entity".
[ ] Add an "album" where you can see an image, name, and special info from each type of enemy that you have already photographed. It can be found in the main library of the town. The info could give hints about the weaknesses of each enemy and even some curiosity.
[ ] Add the final bosses and minibosses that you have already beaten to the battle tower. There will be "simulation chambers" where you can battle against them again (only with the ones you have already beaten in the dungeons). That will allow to take photos if you missed them. You may need to pay certain amount of gems to unlock each boss chamber.
[ ] When you complete the album, something good will happen. I will keep this as a secret for now.
New feature for completionist gamers: