Shop screens, item sort buttons: let ctrl + click apply the same sort to both shop and mule inventories simultaneously. I don't even care if you document or tooltip this feature, I would still use it every single game. Better inherent secondary sort: use level. Rarity, cost and power are not very granular, so having sorted by them still might leave many rows of items to look through. The single most semantically valuable and granular set of values to sort against is level. So sorting by rarity, cost or power should implicitly also sort by level (for items of the same primary sort value). In game tutorial or reference timeline for the timing of card effects. When two things happen "at the beginning of the turn", what order? Is that different than the beginning of *your turn*? etc. Allow Wavering Faith to target allies.
You can target allies with wavering faith (or any other attack card) by holding down ctrl when you click on the attack. Alternatively you can turn auto target to off in the options and then it'll let you click on allies for every card you play. When things happen at the beginning of your turn, attachments happen first from oldest (leftmost) to newest. Then terrain effects occur. So if you have dimensional traveler attached, it will trigger before lava terrain, allowing you to escape it. A tutorial message for this could be nice. I'm not sure what exactly the order is when you sort by rarity, cost, or power, but level would definitely make sense. I'm not sure what you mean by "mule inventories"
If you mean what I think you mean then this can already be done. Left clicking an item on your character sheet sets the filters for both inventory and shop to that item. e.g. click on a warrior's weapon and the shop and mule filters will both change to "Weapon". I suspect this would be solved by making the Card Hunter help page more obvious from inside the game (currently Menu -> Help). This has a breakdown of the order of play.
