The three diamonds and both doors were painted as tiles in TerrainBase, which cannot act as pickups or triggers. Replaced them with real prefabs that reuse the same atlas tiles (diamond = (7,3), doors = (10,6) and (11,5)) and erase their placeholder tile on ready. Collecting all three diamonds unlocks the door; touching it fades to black, pauses the tree and shows the level-clear screen with a next-level button (currently reloads the level, as there is only one). HUD now shows the diamond count.
