I think you nailed the theme of the game, Illusion. I remember as I was trying to come up with an idea, one concept that stood out was changing the perspective, and for me that connected with the camera(point of view) but didn't crystallize into a game concept.
the game is very enjoyable, I especially love that you get to see the girl's reflection as the bird flys up and down, and how you bring the doodles on the walls, which is like very where now a days, to life was very creative.
two things I meant to ask you
1- how did you come up with the idea, what was you mental process? did you use to play this game as a child lol?
2- programming wise: in case this is an endless level, how do you generate the enemies, such that it has an increasing difficulty, is there an alogrithm for that or random?