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.
End the War of Sisters before any blood is shed.
Beat the game on Nightmare mode.
Defeat a boss without stopping time nor taking damage.
Collect all Familiar companions.
Acquire every Orb Spell.
Acquire every Orb Passive.
Find all Melee Orbs.
Obtain an Orb without breaking its pedestal.
Defeat the Ravenlord in battle. (Normal or Nightmare mode only)
Collect all Memories.
Collect all Memories, Letters, and Downloads.
Collect all Downloads.
Prevent the Qaelans from being persecuted by the Empire.
Defeat Nightmare in battle. (Normal or Nightmare mode only)
Discover 100% of the map.
Finish all character quests.
Defeat Cantoran in battle. (Normal or Nightmare mode only)
Finish a character's entire quest line.
Collect all Letters.
Defeat Ifrit in battle. (Normal or Nightmare mode only)
Defeat the Sandman in battle. (Normal or Nightmare mode only)
Defeat the ruler of Lachiem.
Defeat Emperor Nuvius in battle. (Normal or Nightmare mode only)
Defeat Xarion 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)
Defeat the Azure Queen in battle. (Normal or Nightmare mode only)
Finish a character's quest.
Have an Alchemist make you a new Spell.
Have an Alchemist make you a new Passive ring.
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)