Here is the full list of all 23 Iron Danger achievements.
You found the first Shard poking through your chest.
Die 100 times.
Collect 30 mushrooms.
You found the fabled Healer of Brumehead.
You found the second Shard and feel the nature's call.
You found the third Shard, and it makes you shiver.
You found the fourth Shard, and it eases your pain.
You found the fifth Shard. Your enemies tremble before you.
You successfully completed Iron Danger. Congratulations!
Collect 20 berries.
Kill 30 keyus.
Defeat 100 enemies.
You healed the wounded Tyrannogrouse.
You put the Tyrannogrouse out of its misery.
Eat roosterfish roasted over campfire.
Use Earthquake while boosted by fire.
Blow yourself up by shooting explosive arrow while on fire.
Kill the alpha Roosterfish in the temple under Rimfeden.
Take a troll into the Northlander camp.
Find and read the recipe in Kalevala.
Grow stealth grass 20 times.
Hunt down and slay all of the trolls in Bleakshore.
Destroy all three gates leading into the Northlander camp.