Ok, for the error message it looks like you are hitting [start] instead of [a]. [start] is unfortunately off limits for smile basic code, and just stops the code.
As for errors, you add 2 to cy instead of 1 for the down arrow. The biggest problem looks like the last two lines. It looks like you want to break out on [a] but gosub back to the menu line again instead. I think you want to goto....
0そうだね プレイ済み