I really did enjoy my time with the game.
I am not sure if I understood the rule to 100% but I made it to Day 4.
I love Dominion (the board game or rather card game) and played it (and some expansion of it) into the void and +1. So this hits that ick - however it comes to the same questions that arise.
E.g. the base copper coin, your equivalent is the +5 Mechanical/Electrical/Arcane, is something I don't really want more of except there are other symbiotic cards that enable combos. Otherwise they just clunk up your deck. Therefore I would maybe reduce the shops size to 3 - 5 cards and let only new cards appear instead of the base deck ones (except of course there are combos, where you want a specific base card for).
But this is already in the balance-design of your game - so obviously no deductions for that and I know it's hard enough to come up with mechanics for cool card designs in the short span of the jam period.
So I only say, great submission and congratulations to your first game jam submission!
A solid base to work on after the jam!