Here is the full list of all 20 Dance Assembly achievements.
Finish the tutorial.
Save your first creation.
Take a screenshot in-game.
Upload an item to the workshop. Either because you're proud, or...because you'd like to torture others.
Load an item downloaded from the workshop.
Have 10 objects as part of a single creation.
Have 100 objects as part of a single creation.
Have 1000 objects as part of a single creation.
Turn off shadows for an object.
Dance for the first time.
Dance 10 times.
Wow... you really already danced 100 times? You must be good.
Dance 1000 times. 1000? Really? Where did you get the time to do that?
Have one object be the parent of 10 different objects.
Do the best dance in the game.
Remove the default ground object.
Have 20 objects at once with the word "clone" in their name.
Turn off the music.
Dance with no objects in the scene
Have 100 objects at once without a custom name.