I am a big fan & advocate for Bitcoin and don't know anyone in the space who claims Bitcoin is anonymous. In fact everyone talks about how it's not and ways to fix that.
This is fun. I'm gonna show it to my 8 year old, who I suspect will like it, but the problems will be too difficult after just a few levels. Would be cool to have some way to limit the difficulty.
This would also do well on paper, so I wonder if it can be printed.
I have been very happy using fastmail as my email provider and 1password as my password manager. They have an integration which allows you to generate masked emails, which makes what you're describing possible.