In Chocolate Castle, you must see to all the different types of chocolate getting eaten. Each type of animal will eat precisely one specific type of chocolate. The trick is that after an animal eats a contiguous hunk of chocolate, the animal leaves, too. You work around this by sticking same types of chocolate together, by sliding them around from above. Problematically, once you set down two same-type pieces of chocolate, they stick together forever; this is where the puzzling comes in.