100 door codes level 18, the clue on this level is showing on door, you can see picture (food of fish and sort of vertical fish from smallest to bigest fish downward direction). so base on the clue, the objective is object food of fish, and vertical small, medium, and biggest fish.
i will help you, the sequence for the answer is begin from bottom (biggest fish) to top(food of fish)
vertical biggest fish, there is 1 pcs on the picture
vertical medium fish, there is 2 pcs on the picture
vertical small fish, there is 2 pcs on the picture
food of fiss, there is 8 pcs on the picture
so the answer is 1228