I am glad that you like the idea!
Most of my time spent on designing the generation of the notes on the gravestone that is why you can see my menu and other screens are a bit lacking.
I was initially afraid that the key combinations are too overwhelming but once you got the idea it should be easy to memorize.
The key combinations are intended to mimic the way you play an instrument other than a piano, e.g., a guitar where your left hand controls the pitch and right hand fires the notes.