Here is the full list of all 59 The Bard's Tale IV: Directors Cut achievements.
Save the world
Complete the final dungeon
Kill Bishop Henred
Defeat Tarjan
Find the Destiny Wand
Have a Rogue attain the Assassin class
Have a Bard attain the Minstrel class
Summon a Pillar of Flame
Clear the Stronsea Isles of Miasma
Defeat Lagoth Zanta
Have a Practitioner attain the Sorcerer class
Have a Rogue attain the Thief class
Reach level 20
Hoard 10,000 gold
Find the Strifespear
Slay a corrupt paladin
Have an adventurer attain the Saint class
Find the Spectre Snare
Defeat Mangar
Have a Rogue attain the Shadow class
Have a Rogue attain the Saboteur class
Reach level 18
Have a Fighter attain the Commander class
Have a Practitioner attain the Conjurer class
Have a Fighter attain the Defender class
Have a Fighter attain the Vanguard class
Clear the corruption in the Forest of the Inchriach
Have a Bard attain the Rabble-Rouser class
Have a Rogue attain the Dirty Fighter class
Unlock the magic within a puzzle weapon's hilt
Slay a paladin
Unlock the magic within a puzzle weapon's grip
Unlock the magic within a puzzle weapon's pommel
Defeat Gaufroi
Reach level 10
Uncover the secret of sinister street
Discover the gloves of the dead mage's apprentice
Defeat the wraith of Mangar
Use standing stones for the first time
Hire a mercenary
Unlock the secrets of a code wheel statue
Craft your first item
Pray to an Altar of Gratitude
Keep Melody as your starting character
Create a Fighter as your starting character
Create a Practitioner as your starting character
Create a Rogue as your starting character
Create a Bard as your starting character
Defeat the final boss with only 3 party members
Have a Fighter attain the Champion 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 Bard equipped with both the Jesters Shoes and Jesters Cap
Have a Bard attain the Troubadour class
Have a Bard attain the Brewmaster class
Have a Bard attain the War Chanter class
Put King Gaerwyn to rest and restored peace in the Haernhold