I see the lack of in-game tutorial has struck, I had a feeling it would at some point, adding a tutorial is definitely a top priority right now.
The cards are activated abilities, while playing the pinball part of the game they show up on the left side and you can press w or space to use them to do things like have the ball jump or spawn some extra bouncers, this is also why the flippers turn off when you hold them, because some cards give points and being able to keep the ball in one place allows you to infinitely use those cards, which is a pretty boring way of getting infinite points, (otherwise it would be allowed).
The win condition 100% needs to be explained in-game i realize now, tutorial or not. The win condition is to collect enough lives to survive falling out of 6 cabinets, there's a little cabinet stat on the side and if you fall out of the 6th one with enough lives remaining you win!
I'd suggest trying the game again with these mechanics in mind because they really are a big part of the game, but you can do what you want.
Thanks for the feedback! also, secret squirrel.