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