Here is the full list of all 58 Horace achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Push all the rubber ducks into the water in the Laundry Room.
Die 1000 times.
Complete the game.
Reach the end of the game having cleaned one million things.
Don't save the Man in Black.
Win The One Tournament.
Defeat the helicopter boss.
Read 15 teletext pages.
Travel to the secret moon base.
Defeat the Ether boss.
Complete the auto map by visiting every room in the mansion.
Clean 1000000 things.
Find all the secret rooms in the mansion.
Find all the alternate title screen skins.
Score 100 baskets in total.
Defeat the Water boss.
Defeat the Fire boss.
Catch 200 objects.
Buy all possible shop items..
Find a secret room in the mansion.
Defeat the Earth boss.
Defeat the Air boss.
Find an alternate title screen skin.
Get the kids blamed for shop lifting.
Reunite with Heather and the Old Lady.
Go on a most excellent adventure with the Professor.
Run the BASIC program everybody knows and loves...
Meet up with Alice and Sim.
Earn £10000 from jobs, junk yards and other winnings.
Kidnap Mr Deck from the TV Studio.
Clean 100000 things.
Get the high score on all the arcade games.
Take your first train ride.
Watch a train arrive and leave at any station.
Buy an item from a shop.
Help to sort the post.
Earn £1000 from jobs, junk yards and other winnings.
Help to make bricks.
Play an arcade game.
Earn £100 from jobs, junk yards and other winnings.
Help to wash dishes.
Spring Logan from prison.
Learn to play the drums.
Empty 10 bins.
Defeat the Nanobot Boss.
Defeat the K-Bot 100 Boss.
Use the Atlas Gloves to tidy up the village hall.
Of dead Old Men?
Return the blind man's cat.
Rescue the family from the burning house.
Clean 10000 things.
Venture out of the mansion.
Climb walls with the Shoees for the first time.
Clean 1000 things.
Clean up your first thing.
Completed basic robot training.
Complete all other achievements.
Save the Man in Black.