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