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 dungeon levels.
Complete a level containing Shmu.
Complete a time travel level.
Complete "In One Way..." in less than 16 seconds.
Complete "Spike Dodging" without using the teleporter.
Complete "Extending Platform" without using the rope.
Defeat the guardian of the clocktower.
Complete all of the boiler room levels.
Complete all of the gallery levels.
Complete all of the graveyard levels.
Complete all of the clocktower levels.
Complete all the CoOp levels.
Complete all the Teleporting Troubles levels.