I think overall you have the guts of a pretty good deckbuilder, but there's one thing that's spoiling it for me, and that's the starting deck. Traditionally in deckbuilders, the starting deck is a plain, vanilla, uninteresting, but reliable base for you to build your deck off of, and it's nice and thin too so that you have some space to add cards before your deck becomes too bloated.
Like, in Slay the Spire, a character's starter deck will be almost entirely Strike (deal damage to enemy) and Block (stop damage from enemy) cards, with a couple special ones thrown in so you can touch that character's main mechanic.
In Panzer Decks, you get a starter deck that's already pretty bloated to begin with, and which has no duplicate cards (you don't even get a second "Advance" card, it's brutal), and it's even random, which takes away some of that deckbuilding agency when the game throws in a weird card and is just like "hey, take this Strike Left card, it's super hard to use but that's not my problem", and it just bogs down the experience when (depending on the cards I draw), some turns, I just can't move, and other turns, I just can't shoot (I've had turns at the start of a round where I'm just like "well, I can't move towards my opponent, so I guess that nothing's gonna happen right now). I'm used to that feeling in deckbuilders, but I'm used to it happening as a consequence of my actions (taking too many cards and making my deck too bloated, never deciding to remove cards from my deck, etc.), whereas here, it's the default.
I'd really like it if the keywords were simplified some and you got some basic "Move", "Rotate", "Shoot", and maybe "Block" cards, rather than having individual cards for each movement direction, rotation direction, swivel of the barrel (which I think could totally just be made a thing that you don't have at the start! it could be a cool thing to get from a card drop!), two different ways to fire, three different ways to block, and two random cards.
I really wanna play this game! I think you have a really interesting deckbuilder! I just want my starting deck to be good!