There is a balance between making a game to difficult and boring. You were likely talking a moment when the game got boring or repetitive, because you already u

There is a balance between making a game to difficult and boring. You were likely talking a moment when the game got boring or repetitive, because you already understood the mechanics, when you encountered another gameplay tutorial explaining it. Also games might target new players, while you might have encountered similar game mechanics before. But even then a good tutorial will make it fun, although it may be easy to solve. It's also helps to make it solvable fast if you already know the mechanics. But still, if you add a new game mechanics 20 into a game, it is good practice to add a situation where you can learn to handle it. A good example is the gravity gun in half life, or specific features of it that only get available in the endgame.