What are the requirements for the achievements in Ticket to Ride: Europe?
The basic requirement is to purchase the Switzerland map expansion as an in-app purchase and complete the achievements using that map.

For the achievement Chocolate Exporter you must connect all four countries (France, Germany, Austria, and Italy). To complete this, priority number one is to actually connect the four countries. This will take most of your trains and many of your turns. Try and grab as many country tickets as you can, but don't push it, they're relatively high value. Avoid non-country tickets as you probably won't have enough trains to complete them.

Here is an example board showing a victory with all four countries connected


and here is the achievement




For the achievement Valley Commuter you must not claim any tunnel routes on the Switzerland map. To complete this, grab as many tickets as you can that can be completed without a tunnel. It's relatively easy to connect most of the cities that don't require tunnels, at which point many of the tickets you will grab will be already completed.

Here is an example board showing a victory with no tunnel routes claimed


and here is the achievement