The game box has a music function which can brighten your day, when it is opened. If the box does not play or if the music get stuck, the included battery can be exchanged. The included battery is not covered under any warranty.
Instructions for changing the battery can be found here: https://explodingkittens.com/fancybox
Note - the back of the cards in the Nordic version differs from the English version. If you want to mix a Nordic version with an English expansion, we recommend buying sleeves with a covered back.