Here is the full list of all 43 Mr. Bree+ achievements.
Beat all levels without dying
Get all other achievements
Beat 40 levels without dying
Beat 20 levels without dying
Beat your best time 20 times
Beat level 24 in less than 29 seconds
Watch the credits cutscene to the end
Complete all levels in all game modes
Beat 40 levels in hardcore mode
Beat 20 levels in hardcore mode
Get 75% of all achievements
Beat 5 levels in hardcore mode
Die on the first level
Stay still for a while
Start a level in hardcore mode
Skip the last cutscene
Defeat the slaughterhouse boss
Press the red button!
Beat 5 levels without dying
Enter the first slaughterhouse level
Collect all bad memories
Beat your best time 10 times
Get 50% of all achievements
Defeat the forest boss
Beat 40 levels
Collect 20 bad memories
Perform your first double jump
Get Double Jump
Die 100 Times
Get Wall Jump
Beat 20 levels
Die 50 Times
Beat the tenth level
Die 10 times in the same level
Die 5 times in the same level
Get Run
Collect 5 bad memories
Beat 5 levels
Get Crouch
Quit a level
Collect the first bad memory
Die 1 time
Get Jump