A nifty idea reasonably well executed. Reminds me a little bit of Circadian Dice, which is not a bad thing to be compared to. Honestly it would be nice to see more non-roguelike deck/dicebuilders in this vein.

Does suffer a little in that earlier stages require very little tinkering with the default cards while late game it's reasonbly straightforward to construct a deck that ignores the enemy's gimmick entirely and just blows them up on auto pilot. The sweet spot is the middle, where the stage gimmicks demand your attention.