Here is the full list of all 51 The Bard's Tale achievements.
Finished the game on Normal Mode
Used Mannanan's Artifact to summon Mannanan
Finished Chapter 13: The Island Tower
Finished Chapter 12: The Firbolg Mines
Learned the song of the Brute
Collected 10 tokens
Learned the song of the Bodyguard
Collected the Blood Stained Map from the Wandering Trow to unlock secret area
Collected the Weather Stained Map from the Wandering Trow to unlock secret area
Collected the Ancient Parchment Map from the Wandering Trow to unlock secret area
Collected the Ratty Old Map from the Wandering Trow to unlock secret area
Learned the song of the Gouger
Learned the song of the Rogue
Drank 1 beverage in each of the 5 bars: The Drunken Rat, The Aiken Drum, Trowies Pub, The Fat Lute, and The Tup
Learned the song of the Knocker
Finished Chapter 11: Stromness
Learned the song of the Behemoth
Learned the song of the Enchantress
Finished Chapter 10: Greenlands
Finished Chapter 8: Dounby
Participated in the talent show in Dounby
Donated 20,000 silver at the Kirks (churches)
Finished Chapter 9: Finstown
Finished Chapter 7: The Mountain Tower
Used Lugh's Artifact to summon Lugh
Learned the song of the Knight
Collected 5 tokens
Finished Chapter 6: The Mountain Pass
Learned the song of the Elemental
Finished Chapter 3: Kirkwall
Finished Chapter 2: Neversdale Forest
Hunted 1 grouse
Defeated the Bugbear of Houton
Finished Chapter 5: The Forest Tower
Used Herne's Artifact to summon Herne
Learned the song of the Explorer
Finished Chapter 1: Houton
Finished Chapter 4: Highland Park
Learned the song of the Mercenary
Learned the song of the Crone
Learned the song of the Light Fairy
Learned the song of the Heroine
Tipped 30 Cows
Killed 30 chickens
Talked to Roxy the dog
Used Caleigh's Artifact to summon Caleigh
Defeated the rats in the cellar
Learned the song of the Thunder Spider
Finished the game on Easy Mode
Finished the game on Olde School Mode
Collected 20 tokens