I really like the visual and sound element for the puzzles, makes it really satisfying to come up with a solution.
Though I really would've like some clarification of which direction the lines go in, it is very easy to get lost between the lines and at first I barely understood how the paths are connected, I think a little color coding would've gone a long way. And the Selected priority paths being reset when you set new path made for quite a hassle to try out different solutions (though I can imagine that being an annoying technical difficulty you had to work with). And the curve strength modifiers were sometimes a bit too large, I think they should be a bit thinner so you can still see the lines under them.
Those things sadly made me unable to beat the last few levels even though they looked most interesting by far. Level 11, the last one I beat, was by far the most fun to solve. The later ones look even more fun but the controls got in the way and I am getting too tired for hard puzzles (might come back later to complete it).