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