Here is the full list of all 6 Anodyne achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
You found the broom!
You activated the windmill!
You defeated Briar!
You finished the game with over 37 cards, all the health and broom upgrades!
You 100%'d and finished the game in under 3 hours!
You found all 48 cards!