What they mean by "the algorithm" is the learning algorithm, not the actual learned behavior. Historically in machine learning a great deal of hand tuning of le

What they mean by "the algorithm" is the learning algorithm, not the actual learned behavior. Historically in machine learning a great deal of hand tuning of learning algorithms is required for them to even be effective on a single problem, so it's impressive that a single algorithm was able to learn to play many different games effectively. Having a single instance of an algorithm learn to perform well on many different tasks is really a separate problem than what they're dealing with here.