Very nice game! I revisited it a few times now, and today I officially solved it. Here is how it's done easily:
faces:
All cards cost 1
Pierce cards bounce
Bounce cards pierce
Additional bullet per shot
Then I had 2 "refill energy cards", so I could spam, and 3 of the "4 piercing shots" card. Every time I pressed it just cleared the whole board.
For the second half of my game I got a legendary card "add one bullet every time you shoot". I combined this with "next shot bounces" and "next shot is a bomb".
I created a wall of explosion and made it to wave 60 before the lag got problematic :)