I saw you replied to other comments, so figured I'd at least put the info I had up, but didn't expect you to get to it so quick.
Lol, I can only aspire to your greatness.
1. Honestly, it's not that big of a issue, glad to know your aware.
2. Always enemy, I haven't paid attention to the color, but will in the future. It's low probability, I doubt many people will see it.
3. Yeah tested it using my endless King difficulty playthrough and a fresh playthrough. Repeatable early dragon egg event is OP. (Un)Fortunately it's completely controllable.
4. Thanks, good luck. In Rubber Duck we trust.
5. (Sorry, to add more) I don't know if intentional, but feels like a discrepancy. "Faithful Defense" is effected by shield, but "Centaur Defender" is not. With the event +1 shield (Couple in the peep hole) and the boss reward +2 shield (Mystic transformation) "Faithful Defense" becomes really powerful for a 1 cost (10 yellow cards in deck gives you 40 block) that can be extended with other shield granting cards. "Centaur Defender" is harder to extend to this point, requiring 29 strength, for a 2 cost. (best I have come up with is multiple copies of "Ready for Battle" and "Ghoulmancer's Boon" and multiple copies of "Infernal Recall").
Of course, you have made a game that honestly is fun, challenging, and balanced. Sometimes I wish it had a safe mode so I could play it with people over, but hey pretty pictures :D. Thanks for replying and actually listening!
P.S. Ghoulmancer's Boon is GOAT'd!