1. Behind the original
2. Next to the original, extremely translucent
3. Off in the sky, above the main scene
4. Shrinked behind the stage at the bottom
5. Super-shrinked, behind the 2 in 27a
I just finished the challenge (in less than 10 minutes) and now you tell me you've already done it...
anyway i solved 16,1,20,19,18,5,17,15,7 and 13 in order