I can´t thank you enough for all this feedback! Even though I often get carried away with the next project, this is one I am almost sure I´m coming back to, soon. You are right, each card is mostly the same, only the animation, cost and damage change for now. Your suggestion of making specific cards for specific situations/enemies is really good, and goes along well with deckbuilding, as you´ll have to build the right deck for each battle. About having no time to choose what card to play I will probably either use your time slow suggestion (even though I have to make it so it can´t be abused to be in timeslow the whoe game) or have a 10 sec. timer of timeslow or total time stop before each boss attack. Thanks for that one as well, really good idea!
Your comment didn´t feel to me like a rant at all, I really appreciate all the feedback and suggestions, hope I´ll get to all this soon enough so it´s a more interesting and lasting game.