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 the game.
Push all the rubber ducks into the water in the Laundry Room.
Save the Man in Black.
Run the BASIC program everybody knows and loves...
Win The One Tournament.
Defeat the helicopter boss.
Travel to the secret moon base.
Defeat the Ether boss.
Die 1000 times.
Defeat the Water boss.
Catch 200 objects.
Defeat the Fire boss.
Defeat the Air boss.
Buy all possible shop items..
Defeat the Earth boss.
Find a secret room in the mansion.
Find an alternate title screen skin.
Reunite with Heather and the Old Lady.
Go on a most excellent adventure with the Professor.
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.
Help to sort the post.
Buy an item from a shop.
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.
Return the blind man's cat.
Of dead Old Men?
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.
Don't save the Man in Black.
Reach the end of the game having cleaned one million things.
Clean 1000000 things.
Watch a train arrive and leave at any station.
Find all the alternate title screen skins.
Find all the secret rooms in the mansion.
Score 100 baskets in total.
Read 15 teletext pages.
Get the kids blamed for shop lifting.
Complete the auto map by visiting every room in the mansion.