Just a few minor things I noticed while testing the app:
After restarting the app, the crests are displayed in the Western style. However, if you open the Settings, the Japanese crest icon is selected. It looks like the UI and the saved setting get out of sync until you manually switch the option.
Strike Ninja (Card #188): In both the English and German versions, the first ability text seems to be incomplete.
Gearfriend (Card #202): The second ability text looks like it’s overlapping with the bottom border of the card.