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