I think World of Warcraft is the hardest game to play. Because it is the epitome of ‘easy to learn, difficult to master’. If you’re just starting out, the early game experience is very easy, there’s a lot of hand-holding, and the content is quite easy. As you level up, you’ll find your class becomes more complex, content becomes harder, and there are more mechanics to learn and more gold to earn. It’s a fairly gradual process.
Geometry Dash. It might look easy the first time, but lemme just tell you something: Oneline Levels, Slaughterhouse, Abyss of Darkness, and the hardest: The recent Tab. I am not even trying to troll.