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.
Collect all Familiar companions.
Acquire every Orb Passive.
Acquire every Orb Spell.
Find all Melee Orbs.
Defeat the Ravenlord in battle. (Normal or Nightmare mode only)
Finish all character quests.
Defeat Cantoran in battle. (Normal or Nightmare mode only)
Collect all Downloads.
Collect all Memories, Letters, and Downloads.
Discover 100% of the map.
Obtain an Orb without breaking its pedestal.
Collect all Letters.
Defeat Ifrit in battle. (Normal or Nightmare mode only)
Prevent the Qaelans from being persecuted by the Empire.
Defeat Nightmare in battle. (Normal or Nightmare mode only)
Defeat the Sandman in battle. (Normal or Nightmare mode only)
Collect all Memories.
Finish a character's entire quest line.
Defeat Xarion in battle. (Normal or Nightmare mode only)
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 Aelana in battle. (Normal or Nightmare mode only)
Have an Alchemist make you a new Passive ring.
Defeat The Maw in battle. (Normal or Nightmare mode only)
Defeat a boss without stopping time nor taking damage.
Defeat the Golden Idol in battle. (Normal or Nightmare mode only)
Have an Alchemist make you a new Spell.
Finish a character's quest.
Defeat the Azure Queen in battle. (Normal or Nightmare mode only)
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)
Find your first Familiar companion.