I remember this game. It predates mobile phones (or, rather, it predates mobile-phones-smaller-than-a-housebrick) I gather that Nokia adopted the game for their late 1990s mobiles. I think I had a version on the VIC-20 (early Commodore home PC with nice keyboard and very little memory). Dave’s version is prettier.
And every now and then, he tells you a factoid about Parkinson’s (you can continue playing by pressing the return key).