Here is the full list of all 13 Adventures of Shuggy achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Complete all of the gallery levels.
Complete all the CoOp levels.
Complete all the Teleporting Troubles levels.
Defeat the guardian of the clocktower.
Complete all of the clocktower levels.
Complete "Extending Platform" without using the rope.
Complete all of the graveyard levels.
Complete "Spike Dodging" without using the teleporter.
Complete "In One Way..." in less than 16 seconds.
Complete all of the boiler room levels.
Complete all of the dungeon levels.
Complete a level containing Shmu.
Complete a time travel level.