Thanks for playing and I appreciate the detailed review!
I kinda threw in the rocks, barrels, and crates last second so definitely should have done some more visual distinction. Fixing the colliders and adding a different highlight color probably would've helped a ton. I definitely should added a hint system for each NPC if the player can't find the next object they need - maybe a circled search area that narrows down where the object could be..
[Spoiler Warning]
Last time I checked, all quests can be completed to see the Queen's final scene. There is a white flower next to the queen (first item you see) and one next to the glasses on a crate. All of the coins should be under rocks as I tried to hide items of similar categories in similar places, might need to zoom in a bit to see them though.