Great atmospheric soundtrack, very suitable to the theme. Though understated, the narrative aspect here is strong: It really made me wonder where I was, and how I got there.
I understand the esthetic choice to go with totally abstract visuals, but personally I would have preferred a little bit of graphics.
The card play would have been more interesting with more complex cards that can create combos. I was able to beat all 4 opponents just by playing my highest attack card each round (and playing block cards when I ran out of attack cards).