I enjoyed the migrating birds flavour, and the combination of overland travel with a card game is nice.
Is there any cost to playing cards? It felt like I could just click every card in my hand without needing to think about it... I wonder if you could have two challenges at a time, so you have to choose which cards to spend on each one, for example.
Does the terrain affect the encounters you face? I felt like it did, but I may have imagined that.
I thought the use of hanafuda cards was really nice. Overall, the art and music you selected was all very pleasing, and worked together very nicely.