A good start
The app is pretty, but relatively simple. All you can do is assign colors to the notes and listen to preset simple scales or melodies that highlight each note and color together as each note plays. Over time, you would probably start to make color associations with the notes and start to "see" the pitches you are hearing like looking at a painting with your ears. But it would be kinda difficult to remember to do it regularly as the experience doesn't really leave you dying to come back to the app tomorrow. It doesn't have any sort of instruction or gamification with things like varying difficulty levels you can work your way through and track your progress and accuracy. These would be nice additions to see, maybe starting with a few notes and the middle of the keyboard, then progressing to more tones and the higher and lower registers. It could also add an option to change the instrument, starting with simple pure sine waves and showing a progression from the simpler timbres like flute to ones with lots of overtones like French horn or a human voice. It could also have an option for pitch recall at the most advanced level where the device can listen to you hum or sing a note and tell you how far off you were from center. If users submit their game play data,the developer could track whether or not people were actually getting better at pitch recognition, and deliver this data to new users so they know what to expect and how much time they would have to dedicate to learning the skill.