Here is the full list of all 14 Mr. Pumpkin Adventure achievements.
Clear the hidden chapter:No Applause.
Experienced all 3 endings of the game, plus win at the mini-game at least 5 times and fail at least 10 times.
Arrive to the end of the eighth chapter:My way.
Collect all of the diary pieces.
Clear the seventh chapter:The lab.
Arrive to the end of the seventh chapter:The lab.
Arrive to the end of the sixth chapter:The end of the world.
Clear the sixth chapter:The end of the world.
Clear the fifth chapter:The metro.
Clear the fourth chapter:The theater.
Clear the third chapter:Four cubes.
Clear the second chapter:Escaping.
Clear the first chapter:Wake up.
Clear the mini-game for the first time.