Thank you for playing and feedback. The trick to get from this room is to notice you can still see the Witch and thus click on her again. She teleports you back and forth.
I playtested the game like hundred times and finished puzzles in all possible orders to ensure players can't get the game to an unfinishable state. I really thought it through and that was actually the most work done on the game. Implementation was then rather easy because Unity is a great engine that does for us a lot :)