Here is the full list of all 11 The Wonderful End of the World achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Obtain 12 A+ grades.
Grab a massive 10,000 or more objects.
Steal a clipper ship in Rice Cake Parade.
Steal a donut in the Bibliodiscotheque.
Explicitly reset the game, then complete the entire thing in one sitting.
Complete the Megalopolis level.
Steal the brontosaurus in Bumble Burbs.
Steal the Orangutan in the Bibliodiscotheque.
Grab 2,500 or more objects.
Devour half the world by finishing 6 of the 12 levels.
Grab 500 or more objects.