Here is the full list of all 58 The Bard's Tale IV achievements.
Defeat Gaufroi
Slay a paladin
Uncover the secret of sinister street
Have a Practitioner attain the Conjurer class
Unlock the magic within a puzzle weapon's pommel
Reach level 10
Discover the gloves of the dead mage's apprentice
Defeat the wraith of Mangar
Use standing stones for the first time
Hire a mercenary
Craft your first item
Create a practitioner as your starting character
Prey to an Alter of Gratitude
Create a bard as your starting character
Keep melody as your starting character
Create a fighter in the initial character creation level
Create a Rogue as your starting character
Reach level 18
Reach level 20
Save the world
Unlock the secrets of a code wheel statue
Find the Spectre Snare
Find the Destiny Wand
Find the Strifespear
Clear the corruption in the Forest of the Inchriach
Clear the Stronsea Isles of Miasma
Defeat the final boss with only 3 party members.
Hoard 10,000 gold
Blow the Fire Horn
Slay a corrupt paladin
Kill Bishop Henred
Unlock the magic within a puzzle weapon's grip
Unlock the magic within a puzzle weapon's hilt
Defeat Mangar
Defeat Lagoth Zanta
Defeat Tarjan
Complete the final dungeon
Have a Fighter attain the Champion class
Have a Fighter attain the Commander class
Have a Fighter attain the Defender class
Have a Fighter attain the Vanguard class
Have a Fighter attain the Veteran class
Have a Practitioner attain the Archmage class
Have a Practitioner attain the Magician class
Have a Practitioner attain the Wizard class
Have a Practitioner attain the Sorcerer class
Have a Rogue attain the Assassin class
Have a Rogue attain the Thief class
Have a Rogue attain the Saboteur class
Have a Rogue attain the Shadow class
Have a Rogue attain the Dirty Fighter class
Have a bard equipped with both the Jesters Shoes and Jesters Cap
Have a Bard attain the Minstrel class
Have a Bard attain the Troubadour class
Have a Bard attain the Brewmaster class
Have a Bard attain the Rabble-Rouser class
Have a Bard attain the War Chanter class
Have an adventurer attain the Saint class