1. those relics give a strong upside with 1 more mana, and you only play 1 more stage until the game is finished (after 3 stages officially)
2. The game and the modes are not fully balanced yet, but thanks for your feedback.
3. Yeah, the endless mode is only a placeholder. I will keep some sort of endless mode in the game, where I could change that. But stage 1 cards are usually weaker, or what do you miss from there?