A key rule in Find the Princess is the rule that allows players to teleport to a coin when moving towards it in the same line. This is a unique rule that changes the game greatly, because understanding this rule as early as possible makes beating the game a lot easier. My first playthrough, I got almost all the way through the game before I realized that I could teleport through walls by positioning the avatar in line with a coin that I want to teleport to. This meant that I was completing all of the mazes regularly. It is still possible to complete the game this way, but this rule adds another dimension. It allows players to beat the game faster, but also gives players a completely different mindset for each level. Rather than looking for pathways in the maze, they will be looking for coins near the princess. This is what I did on my second playthrough.
Another key aspect of the rule is that it can only be used once for each coin. This requires players to avoid moving towards a coin unless they want to teleport to it. There is one instance in the last level where I teleported to a coin near the princess, but then accidentally teleported back to a coin in the middle of the maze while trying to get to her. In this way, the rule can make the game easier in some circumstances and harder in others. Understanding this rule throughout my second playthrough made it seem like a completely different game, which is why it is so important.