Thank you for your feedback!
I don't think you are stupid/alone in being stuck. I find escape rooms pretty difficult even without time hopping shenanigans. We have updated our game's description to include solutions.
Thank you for playing my game! The Void Demon is supposed to be intimidating and appear undefeatable. There is no single card that drastically boost damage output but there are multiple card combinations that consistently scale damage output. They can be tricky to find and create.
My current fastest run in defeating the Void Demon is just over a minute: 1:08.319 (there's a speedrun clock in the endscreen).
Thanks for the feedback.
The last level is supposed to be impossible. For the theme, I was trying to emulate the feeling of playing a competitive game where your teammate is throwing. I should have coveyed and expanded on that idea more but I was sort of tilted by the end of the jam. Maybe the real emotions are the emotions we made along the way.