But he isn't playing it any different. It says in the articled that it took 300 to 400 hours over 4 years and that he played it when he had some minutes to spar

But he isn't playing it any different. It says in the articled that it took 300 to 400 hours over 4 years and that he played it when he had some minutes to spare, like on a bus or the toilet. That's how most casual games are played. The only notable here is that the game is seemingly repetitive, but even there each level is different and requires a new way to hit the ball. People have played Counter Strike on de_dust2 (a specific map) for almost two decades as this point. They play the same map over and over again, is it repetitive? Maybe, but each time there are new people so it makes it a new challenge each time. People have played solitaire for their whole lives, again the dynamic comes on each "level" (i.e. new shuffle). I am 100% sure that the play time of these people dwarfs this guys play time many many many times over.