Rock Band Blitz is Harmonix's next effort to revive rhythm games, a creation that uses a standard console controller rather than specialized music peripherals. At PAX East 2012, the team showed off video of the game in action and explained a little more of its genesis.
Its first builds were too easy and, therefore, too boring, according to the panel. So a programmer suggested that Rock Band Blitz completely remove difficulties, because the expert track seemed to be the most fun for players. In easy modes, players were just hopping from one track/instrument to the next (the "Pre-Blitz" game seen in the video below) out of boredom and the note placements seemed totally at random; on expert, they were actually rising to the challenge because the commands were more in rhythm.
The game is pretty much done, says Harmonix. They're just working on polish and balance. The development team really strove to emulate the "Rock City" feel of Rock Band 3.
Harmonix showed off an early prototype of Rock Band Blitz, which they refer to as Pre-Blitz. This is what Blitz looked like before they enlisted in the help of a new team of developers in the Summer to help transform the game into a style more closely resembling Rock Band 3.