Tiny King

Once upon a time, there was a tiny, but contented king that rules the land.  All of his subjects were happy with how he runs things on his kingdom, so they created a cake to thank him.  The king loves the cake, but it was dark and he was tired so he left the cake on his table and went on to sleep.  However, when he woke up, the cake was missing.   You need to help the king find the cake.  You will need to find the key to another world before you can go there.  However, you need to figure out how to get the key in each world.