Yep the game needs a LOT of polishing and maybe a complete look overhaul, come to think of it.
The permanent peg placement was a conscious game design decision, as I want to encourage the players to try a new plan each time they fail. It's about creatively building your path to the victory, within number constraints.
However, I'll try to find a way to inculcate granular editing of pegs, along with what I want to achieve.
I truly appreciate your kind words and trying out my little solo outing :)