I wrote this instrument for my daily keyboard practice and it is rather different from those I wrote before (mainly to be used in a DAW). In electronic instruments I was missing the change of timbre with velocity which you have in natural instruments or velocity-sampled ones. So I made the parameters of a simple subtractive synth (as filter settings, ADSR shape, tremolo) depedent on both the pitch and velocity played. In a training session the user fixes the parameter at certain pitches and velocities. These are interpolated during the preformance. The instrument and documentation can be downloaded here: https://gitlab.com/RZ-FZJ/rz-cabbage-recipes and there is a demo here: https://gitlab.com/RZ-FZJ/rz-cabbage-recipes/-/blob/master/Demos/Morpheus_demo.mp3 (please excuse my lousy playing).
(There are also demos of Etude#1 and Etude#2 on the same directory https://gitlab.com/RZ-FZJ/rz-cabbage-recipes/-/blob/master/Demos but I have to admit that the former also uses different synths for some voices.)