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