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