Oh, I got it. If you want to know how to do the puzzle, read below:
Turn the lights off, double click the door in the mirror to reveal a Christmas tree, click the ceiling in the mirror to reveal a string of lights, double click the top half of the door to reveal a wreath, click the top spiderweb to get rid of it, and click the 2nd wind chime piece from the right to make it turn gold, drag it to the door knob, and open the present that you see inside to find hangman. At some point you can put a few drops of those liquids on the bottom left into the plant by dragging them above it, but I dunno if those have any consequence. When I did it, I got some lame Prisoner of Azkaban thing.