Here is the full list of all 26 Ampersat achievements.
Gain all Perks
Beat the Well's 100th level
Fill the Bestiary
Return all Lost Items
Capture all Bonus Words
Open the Portal to Lord Z
Gain 3rd Ring Bonus Perk
Fully Upgrade Well
Make the Gem Merchant appear
Gain 2nd Ring Bonus Perk
Fully Upgrade Freya's Statue
Open the Well
Defeat a Tower
Fully Upgrade Skadi's Statue
Fully Upgrade Weapon Shop
Fully Upgrade Armor Shop
Gain 1st Ring Bonus Perk
Defeat all Dungeons
Fully Upgrade Inn
Sniff out all Secret Chests
Defeat a Dungeon
Find a Secret Chest
Capture a Bonus Word
Consult the Bestiary
Gain a Rank
Ostensibly read the "How To"