Started very late because of lack of ideas. Anyhow, this one is about how perspective is a subjective thing …
Theme is in it, if you play it through you can even see it. :)
(Fun fact: I didn't play through the last level yet. I hope it's beatable. :P)
If you get stuck at the 2nd level, think outside the box!
[EVEN MORE SPOILER]
If you think you've cleaned the room, but didn't win the 2nd level, there still might be something in there. (Hint: This is not a pixel hunt.)