Maybe not merge Liechtenstein with Vorarlberg since it’s a separate country on its own? I think either grey Liechtenstein out or divide it into its first-level municipalities.
I really like this Quiz, but one proposal would be to accept "Basel-Land" for "Basel-Landschaft". In all my time in Switzerland i never heard anyone call it by its full name. But the answer is technically correct like this, so it's still fine if you leave it be.