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.
Save the Man in Black.
Read 15 teletext pages.
Run the BASIC program everybody knows and loves...
Win The One Tournament.
Defeat the helicopter boss.
Die 1000 times.
Travel to the secret moon base.
Defeat the Ether boss.
Buy all possible shop items..
Defeat the Water boss.
Score 100 baskets in total.
Find a secret room in the mansion.
Defeat the Fire boss.
Defeat the Air boss.
Get the kids blamed for shop lifting.
Catch 200 objects.
Defeat the Earth boss.
Find an alternate title screen skin.
Reunite with Heather and the Old Lady.
Go on a most excellent adventure with the Professor.
Clean 100000 things.
Watch a train arrive and leave at any station.
Meet up with Alice and Sim.
Get the high score on all the arcade games.
Earn £10000 from jobs, junk yards and other winnings.
Buy an item from a shop.
Kidnap Mr Deck from the TV Studio.
Help to sort the post.
Take your first train ride.
Help to make bricks.
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.
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.
Find all the alternate title screen skins.
Find all the secret rooms in the mansion.
Push all the rubber ducks into the water in the Laundry Room.
Complete the auto map by visiting every room in the mansion.