Very neat! I'd love a feature where I can share my score with a link to the website (although it's possible there already is one and I just missed it).
No, you didn't miss it. I will implement that either today or tomorrow. If you don't mind to answer: do you have any other feedback? Is the win criteria of ±10% good? Or should it be loosened up to ±25%?
I think the win criteria is good. I would think about automatically showing the "How to Play" screen on a user's first visit so that they are aware of the criteria.