Really nice art style (I particularly like the card art), and using cards for digging is a fun idea.
I'm not sure about the real-time enemies because the cards play-out quite slowly so it can be very difficult to time your movements - I think it would be improved if either the card effects started instantly or the enemies were slower or even turn-based.
If you did want to build on the idea, I could see it potentially being a fun little deck builder if there was a wider variety of different cards and the player could mix up what they wanted to bring with them.