Here is the full list of all 20 Kathy Rain achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Finished the game
Finished day four
Finished day three
Lost track of time on the road
Finished day two
Learned a cold hard truth about your face
Finished day one
Felt like literally taking the wheelchair for a spin
Reunited with a furry friend
Tortured an imprisoned bum
Made your best efforts to miss the funeral
Felt no apparent need to let Lenny down gently
Rediscovered yourself as a creature of the night
Engaged in flirtatious behavior on the computer
Barely resisted the urge to barbeque a bear
Amplified Goober's lung cancer
Totally mesmerized by Goober's monologues
Wanted to engage in a good 'ol book burning
Really had it out for Goober
Became a huge fan of those sweet, addictive, not to mention cancer-inducing sticks of tobacco