Here is the full list of all 53 The Basement Collection achievements.
100% the basement collection
Complete Spewer Bonus Chapter
Complete Spewer Chapter 5
Unlock all bonus content
Complete Triachnid
Find and collect all the lost larva in Triachnid
100% Meat Boy
Complete Spewer Chapter 4
Complete Spewer Chapter 3
Complete Spewer Chapter 2
Find the Skinless Boy
Find the Paradox
Find the Demon
Find the Crybaby
Find the Lost Bird
Create and play a custom level in Spewer
Find the Glutton
Find the lost spaceman
Discover the Moon of Gravida
Complete Spewer Chapter 1
Complete the Unknown in Time Fcuk
Complete chapter 2 in Time Fcuk
Complete the game the wrong way in Time Fcuk
Complete the game the right way in Time Fcuk
Make even more progress through the main game in Time Fcuk
Complete bonus chapter in Meat Boy
Beat Expert Mode in Grey Matter
Get XXXXX points in one playthrough in Grey Matter
???
Come full circle in Coil
Discover the Moon of Debasa
Finish the Game
Discover the Moon of Earth
Discover the Moon's of Bibulon
Beat Boss Rush in Grey Matter
Beat Mormal Mode in Grey Matter
Get XXXX points in one playthrough in Grey Matter
Make more progress through the main game in Time Fcuk
Create a level in the editor in Time Fcuk
Complete chapter three in Meat Boy
Collect 16 bandaids in Meat Boy
Complete chapter two in Meat Boy
Collect 8 bandaids in Meat Boy
Discover the Moon of Malaisus
Find the runaway
Complete chapter one in Meat Boy
Make progress through the main game in Time Fcuk
Get XXX points in one playthrough in Grey Matter
Collect 4 bandaids in Meat Boy