Here is the full list of all 14 The Great Perhaps achievements.
Finish the game
Get rid of all time anomalies
Repair the unusual machine
Find all hidden keys
Don't worry, no animals were harmed
Treat Carl to his favourite formula
Find out who's waiting for you at home
Save the hostages
Give hope to the desperate writer
Help two lovers get together
Make the spoiled child happy
Catch a ride
Hear what the teddy bear has to say
This is where the fun part begins