Overall, I think this is a neat feature to add to the game.
Waking up to see 5 more keys in a chest was a welcome site today. And it spawns questions for me:
Will that be an ongoing thing?
If so, do we have to use the keys each day to get additional keys?
What are the plans for adding higher rarity dragons? Will they use the same keys with higher counts? Is it possible to bank keys now to use for access to better dragons later, or should we assume we need to use everything we get and just hope for more down the line?
Like many, I wouldn't ever spend 120 gems on a common dragon, or keys for a common dragon. We'd need to be talking Legendary or Heroic before I approach that kind of spending.
I'm also wondering: Are we able to start a rescue, get some of the orbs, and then switch to a new rescue? Or does every rescue we start have to go all the way to the finish before we can do a new one?
I'll experiment with some of these questions tomorrow.