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 "anger".
Beat "denial".
Successfully spin around a rotating block.
Fail 10 times in a wave before completing it.
Beat "ignorance".
Beat the first wave.
Try the infinite mode.
Successfully navigate invisible blocks.
Beat "bargaining".
Beat "guilt".
Beat "depression".
Beat "hope".
Beat "acceptance".
Beat "revolution".
Beat "resilience".
Beat "quickening".
Beat "transcendence".
Beat "trust".
Beat "understanding".
Beat "control".
Beat "identity".
Beat "initiative".
Beat "intimacy".
Beat "integrity".
Beat "anticipation".
Beat "ambition".
Beat "tension".
Beat "perspective".
Beat "release".
Get at least 250 in infinite mode.
Get at least 750 in infinite mode.
Earn at least 1500 in infinite mode.
Beat all of "ignorance" without hitting a wall.
Beat all of "denial" without hitting a wall.
Beat all of "anger" without hitting a wall.
Beat all of "bargaining" without hitting a wall.
Beat all of "guilt" without hitting a wall.
Beat all of "depression" without hitting a wall.
Beat all of "hope" without hitting a wall.
Beat all of "acceptance" without hitting a wall.
Beat all of "revolution" without hitting a wall.
Beat all of "resilience" without hitting a wall.
Beat all of "quickening" without hitting a wall.
Beat all of "transcendence" without hitting a wall.
Beat all of "trust" without hitting a wall.
Beat all of "understanding" without hitting a wall.
Beat all of "control" without hitting a wall.
Beat all of "identity" without hitting a wall.
Beat all of "initiative" without hitting a wall.
Beat all of "intimacy" without hitting a wall.
Beat all of "integrity" without hitting a wall.
Beat all of "anticipation" without hitting a wall.
Beat all of "ambition" without hitting a wall.
Beat all of "tension" without hitting a wall.
Beat all of "perspective" without hitting a wall.
Beat all of "release" without hitting a wall.
Beat the game and watch the end sequence credits to the end.
Beat one daily challenge.
Beat ten daily challenges.
Beat three daily challenges in a row.
Beat seven daily challenges in a row.
Beat five advanced daily challenges.
Beat 100 daily challenges.
Beat "continuance" wave 10.
Beat "continuance" wave 100.
Beat "continuance" wave 1000.
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.