: Look for hidden alcoves behind large trees and within the hollowed trunks.
: It is necessary to see everything the game offers beyond just the main 2.5-hour story. Castle of Illusion HD
If you are looking for other specific collectibles, you may also want to find the or the 71 Chili Peppers hidden throughout the levels. : Look for hidden alcoves behind large trees
: Finding all 10 is required for the "Masters of Illusion" achievement/trophy. Castle of Illusion HD
: Check the underwater cave systems, specifically near the ruins where skellyfish are present.