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