Here is the full list of all 29 Dream achievements.
Find the mess on floor one.
Finish Act Three's Nightmare.
Finish Act Three.
Leave on all the lights before sleeping.
Play the first bar of 'Counting Sheep'.
Finish Act Two.
Finish Act Two's Nightmare.
Eat all the cupcakes.
Finish Act One's Nightmare.
Finish Act One.
Finish the graveyard puzzle in ten moves or less.
Find the memories of an old experiment.
Epic support needed...
Show off your festive side.
Collect all the Dream bible pages.
Visit all the side dreams.
Finish all four mazes without getting caught.
Find a past project.