No missable achievements (plus 20 unknown)
Sign in with Steam or Xbox to track your progress, and:
Read the employee handbook
Listen to the radio show in your Soul Village
Find half of the blue ducks
Get the monorail to the Mainframe
Get crushed by a bookcase in the Library
Complete the full game
Go down the wrong path in the Fairground Zero Level
Complete the planet puzzle in the School Level without checking the answer
Make the right choice in the Library
Complete the Final Level in record time
Complete the Hospital Level without a torch
Find the alternative ending
Complete the Street Level without taking a hit
Complete the Aeroplane Level without dying
Touch the whale on the Beach Zero Level
Hit all the viruses in the Graveyard Level
Find all of the blue ducks
Complete the full game in Welsh