Here is the full list of all 27 The Slater achievements.
Complete level 1 as Master
Shoot a rat
Complete the game
Complete level 6 as Master
Kill a rat
Complete level 5
Complete level 5 as Master
Trigger police station upstairs alarm
Chat with street bum
Shoot a bird
Complete level 4 as Master
Complete level 4
Enter a secret observation room
Sabotage ventilation system
Trigger a car alarm
Dress as lab worker
Complete level 3
Complete level 3 as Master
Shut down a metal detector
Complete level 2
Complete level 2 as Master
Start a lawn mower
Get party invitation without a kill
Sabotage all security cameras in a level
Poison a drink
Complete level 1
Kill a junkie