Here is the full list of all 37 Timespinner achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Achieve all possible feats on the same save file.
Acquire every Orb Passive.
Prevent the Qaelans from being persecuted by the Empire.
Acquire every Orb Spell.
Collect all Familiar companions.
End the War of Sisters before any blood is shed.
Defeat Nightmare in battle. (Normal or Nightmare mode only)
Defeat the Sandman in battle. (Normal or Nightmare mode only)
Discover 100% of the map.
Find all Melee Orbs.
Defeat the Ravenlord in battle. (Normal or Nightmare mode only)
Obtain an Orb without breaking its pedestal.
Defeat Ifrit in battle. (Normal or Nightmare mode only)
Collect all Letters.
Collect all Memories, Letters, and Downloads.
Collect all Memories.
Defeat a boss without stopping time nor taking damage.
Beat the game on Nightmare mode.
Finish all character quests.
Defeat Xarion in battle. (Normal or Nightmare mode only)
Defeat Cantoran in battle. (Normal or Nightmare mode only)
Finish a character's entire quest line.
Collect all Downloads.
Have an Alchemist make you a new Spell.
Have an Alchemist make you a new Passive ring.
Defeat the ruler of Lachiem.
Defeat Emperor Nuvius in battle. (Normal or Nightmare mode only)
Defeat Genza in battle. (Normal or Nightmare mode only)
Defeat The Maw in battle. (Normal or Nightmare mode only)
Defeat Aelana in battle. (Normal or Nightmare mode only)
Defeat the Golden Idol in battle. (Normal or Nightmare mode only)
Finish a character's quest.
Defeat the Azure Queen in battle. (Normal or Nightmare mode only)
Find your first Familiar companion.
Defeat Varndagroth in battle. (Normal or Nightmare mode only)
Find a new Melee Orb.
Defeat the Feline Sentry in battle. (Normal or Nightmare mode only)