Fun game!
What was the algorithm for judging the shapes?
Some images where a bit rough to attempt with a single line, like the boats.
It looks at the percentage of all black pixels inside your shape and gives penalties for every white pixel that made the cut too.
I see! If you wish to expand the game, I think some very simple machine learning algorithms that could give very good results!
They can recognize patterns instead of doing a pixel per pixel comparison, which is more similar to how a human compares images.