Harmonix' Greg LoPiccolo said that the gameplay has been in the company's games all along, but it just took a while for them to present it in a way that people would grasp what it was about.
Speaking to GamesIndustry.biz, the project leader for Guitar Hero and Rock Band said that they put a lot of work into Frequency and Amplitude - which he considered somewhat ground-breaking concepts in their time.
"I remain really proud of them - I think they're great games - but the thing we learned from those games is that an abstract concept is very hard for people to get their heads around," he said.
