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