Fun mod, thanks for sharing. Some things I noticed that might need changing or fixing:

Ethereal cards should have "Ethereal" at the top of the card, to match the base game
"Unleash the Falcon" should say "heal 1 HP" instead of "heal 1 life" to match the base game
"Trappers Delight" should say "play" instead of "cast", to match the base game
"Trappers Delight" should clarify the first trap played each turn
"Trappers Delight" should have an apostrophe in the spelling, "Trapper's Delight"
"Primevil Lotus" should be spelled "Primeval Lotus"
The bond tooltip on the character while in combat could get changed to match the tooltip used for the cards, since the card tooltip is a little more clear
"Dodge" is not triggering combo synergies properly, eg it won't trigger starter relic
"Aerial Support" should clarify that the 8 / 10 initial damage is dealt to all enemies
The "Aerial Support" buff tooltip says that it deals 0 damage, but the damage is dealt normally and matches what the card says

I didn't get a chance to use the "Opening" type cards, but it isn't completely clear if you can't play them at all if they aren't the 1st/2nd card you play, or if they just won't do anything if they aren't the 1st/2nd card

The "Falcon Punch" and "The Wall" cards could be worded a little more clearly for what they do. Maybe instead of "Doing so deals 8 damage again" it could be written as "If you exhaust at least 1 card, deal 8 damage again". I wasn't sure at first if I could get the bonus without exhausting anything, or if I could get the bonus more than once if I exhausted more than one card.

The "Falcon Punch" and "The Wall" cards will also give their bonuses if they became zero cost without any other zero cost cards in hand, without exhausting themselves (eg if you used Madness or Snecko eye). Not sure if this is intended behaviour.

Again, fun mod. I managed to beat the Heart on A1 with a bond-scaling deck that had Snecko Eye and a bottled Falcon Form, with a second Falcon Form in the deck, so I ended up getting to play a bunch of extra cards for free from the deck each turn. Thanks for sharing with the community!