Cool game! Very unique concept. The music is nice, it reminds me of the music that would play in the select screen for the PlayStation 1 jam pack demo disc.
I do wish the enemies would give you more feedback when you hit them, like maybe flashing red and making a *grunt* sound effect or something. It would also be nice if there were a pause menu where you could change the mouse sensitivity as your playing.
There are a few bugs, like sometimes I would draw a "null" card. Also, when you go back to the deck-building screen after dying, you have to reset the cards even though there's none there.
Nice work!