It is an artistic resource that uses the position of objects to make them appear to have different sizes than normal.
Usually, it is used to give the sensation of the existence of giant humans or miniatures.
The inefficiencies of this artistic resource are that objects are always superimposed over others (thus removing the sense of interaction between objects) and that in order to produce an image one has to be in the proper place with the right objects.
Here it seems that the heroine is a giantess near a hill...
...but it was only an illusion.
It is not a montage. There are rooms designed to make fun of the prospect.
So there seems to be a big difference in size, but...
...seen from another angle is not so.
Vomiting a rainbow.
Playing with gravity.
Making fun of gravity.
The incongruity between the sharpness of the hand and the tower ruins everything.
If the shadows were congruent, it would not look so much like a montage.