Good question! I don't think we can do anything with the extra ton of cards. Seems like if we got more than one set we could turn them in for an additional reward. I would like that. It seems pointless to collect cards after you get the reward.

In the app, go to the main screen where your character builds bridges. Click on the red button in the lower right-hand corner. This will take you to an information pop-up page. Select 'settings' at the top of the page you can turn off the music.