20 Copyright protected designs play a backing track and show a fingering map that enables, "jamming over changes". It makes beginning and intermediate musicians feel like rockstars. There are 20 designs with 39 game challenges each. All have highly search relevant names and are ready for the store. Guitar, Piano, Violin, Mandolin, Ukelele, virtually any instrument. Prototype is 4 stars and .99 is appropriate based on 6 months of market research.