Here is the full list of all 76 Duet achievements.
The base game contains 66 achievements, and there is 1 DLC pack containing 10 achievements.
Beat "confusion".
Beat "relief".
Beat "resentment".
Beat "reunion".
Beat "reintegration".
Beat all of "confusion" without hitting a wall.
Beat all of "relief" without hitting a wall.
Beat all of "resentment" without hitting a wall.
Beat all of "reunion" without hitting a wall.
Beat all of "reintegration" without hitting a wall.