Full list of all 42 Cuphead achievements. It takes around 15-20 hours to unlock all of the achievements in the base game on Windows.
The base game contains 28 achievements, and there is 1 DLC pack containing 14 achievements.
Defeat a boss using only the mini-plane bullets
Obtain an A-Rank or higher on all bosses in Inkwell Isle III
Obtain an A-Rank or higher on all bosses in Inkwell Isle II
Obtain an A-Rank or higher on all bosses in Inkwell Isle I
Complete the game on Expert
Obtain an A-Rank or higher on all bosses in Inkwell Hell
Buy everything in Porkrind's Shop
Get every coin in all of the levels
Get every coin in the game
Complete all levels without killing an enemy
Get an S-Rank
Complete the game on Normal
Defeat the Devil
Give in to the Devil
Complete the Casino
Defeat every boss in Inkwell Isle III
Obtain all Super Arts
Parry five times before hitting the ground
Defeat every boss in Inkwell Isle II
Defeat a boss with a Super Art
Defeat a boss with an Extra Special move
Complete a level without getting hit
Complete 100 parries
Defeat every boss in Inkwell Isle I
Defeat a boss
Find a shortcut
Complete 20 parries
Obtain an A-Rank or Higher on all bosses in Inkwell Isle IV
Defeat 10 bosses with Ms. Chalice
Defeat the King's Gauntlet
Have 9HP at one time
Defeat a boss on Inkwell Isle IV without killing any of its minions
Get an S-Rank on a stage of Inkwell Isle IV
Defeat all of the King of Games' Champions
Defeat a boss with one of Ms. Chalice's Super Arts
Complete your quest on Inkwell Isle IV
Defeat every boss in Inkwell Isle IV
Defeat a boss with one of Porkrind's new weapons
Defeat a boss with Ms. Chalice