Here is the full list of all 7 Double Memory achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Complete the Final Stage
Complete Stage 5B or higher without losing an energy box.
Complete Stage 6A, 6B and 6C.
Complete Stage 6C in less than 16 seconds.
Complete Stage 5C in less than 18 seconds.
Complete Stage 2C in less than 20 seconds.
Complete Stage 1A, 1B and 1C.