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