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