A short and competent base to build on. 

I would like to have seen {UI refinements like num-pad/input support, deselect, popup-reference/help, etc} to improve the first time experience; 
And {data saving keeping to allow for highscores, optimized solutions, etc} to encourace replay with more complex levels (not longer...) following the set(s) we do see.

I can see a number of ways that convolution can be applied to generate additional levels from saved solutions, incrementally; But without a pool of solutions from different people to draw from, resulting solutions would tend to be repetitive.
(Alt. game mode that adds incompatible datasets after generating a feasible solution to avoid repetition?)

Overall this looks like a great prototype to build on.