That's a very cool prototype! Some thought:
There's a helpful tip about the cards being flipped from move to attack at the start of a round. Maybe after the player uses their first card, you could follow it up with another tip pointing out that the card is flipped, and that they can use card to attack after ending their turn. It took me a long time to figure that out.
There should be some way to cancel an attack. I sometimes picked an attack but found I couldn't use it, and had to waste it to continue. It seems like that happened after I already had another attack or move selected, and then selected another one?
Before using an attack, I couldn't predict what direction I would be able to shoot in. I eventually figured out that (at least with railgun, machine gun, and shotgun) I could shoot in front of me, to the side the gun was on (on arms) and 45 degrees diagonally on the side the gun was on. But is that always the case? I would be nice to see the attack pattern for an attack.
Lastly, I broke off the legs and one arm of an enemy, and he could still move. I know that hampers the enemies movement because they've got fewer available cards, but it still felt pretty, well, silly, to see the enemy move. I'm not sure how to do much about that, though.