Here is the full list of all 52 Dawnsbury Days achievements.
Win all encounters in the "Additional scenarios" encounter group. You don't need to win the "Training Grounds" encounter.
Have all four heroes be Undetected at the same time.
Win the whole adventure path without ever buying an item from the shop (not even during character creation).
Win an encounter without casting spells or making Strikes.
Win all encounters of the main adventure path on Hard difficulty or above.
Win all encounters of the main adventure path on Insane difficulty.
Score a critical hit on a roll where you have 100% crit chance.
Kill three or more creatures using a single spell.
Inflict positive damage on an undead with Heal.
Win an encounter with four characters of the same class.
Score a hit 10 times because of +1 circumstance or status bonus.
Drain bonded item to regain a spell slot.
Deal at least 50 damage to a single creature with a single combat action.
Command an animal companion.
Unleash your psyche.
Perform a flurry of blows.
Make a Spellstrike.
Re-engage your kinetic aura mid-combat.
Make an attack of opportunity.
Double-kill the demon lord and save Dawnsbury.
Clear the skies of Dawnsbury.
Defeat the remaining dark poets.
Cast a spell of 3rd level or higher.
Protect merfolk children from an attack.
Survive an ambush on the open seas.
Defeat 80 enemy creatures.
Protect and retrieve the prismatic key.
Defeat the demon in the town sewers.
Protect the Golden Candelabra.
Protect the walls of Dawnsbury.
Defeat the squad that teleported in.
Cause an enemy creature to suffer from 3 different debuffs at the same time.
Grapple an enemy creature.
Save Morning Dewdrop's sister.
Open the gate with superior locks.
Defeat the dark shaman.
Survive a dangerous night.
Defeat the protectors of the old manor.
Save Morning Dewdrop from the elementals.
Retrieve the Golden Candelabra.
Have 3 buffs on a single hero at the same time.
Defeat the dark skeleton.
Deal extra damage because of a creature's weakness
Defeat the protectors of the abandoned temple.
Activate a blood magic effect.
Make a Strike with a +1 striking weapon.
Make a Strike with a +1 weapon.
Defeat a kobold ambush.
Defeat puny kobolds.
Inflict sneak attack damage.
Enter a rage.
Kill an enemy with a critical hit.