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
Lost track of time on the road
Finished day three
Finished day two
Finished day one
Reunited with a furry friend
Made your best efforts to miss the funeral
Felt like literally taking the wheelchair for a spin
Tortured an imprisoned bum
Felt no apparent need to let Lenny down gently
Rediscovered yourself as a creature of the night
Engaged in flirtatious behavior on the computer
Learned a cold hard truth about your face
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