Edge: Harmonix’s journey towards its masterpiece has been one of many highways, each a turn towards the ultimate synthesis of music and videogames. This latest has become known as ‘the one that actually teaches you to play instruments’, but in truth they all are. Even Frequency, which turned the PlayStation pad into a kind of Eno-esque navigator of obscure electronica, is as valid a tutor as this game. The obstacles feel just as tall, the need to climb them as strong. The only difference is that the rewards are so much greater.