Here is the full list of all 28 KIN achievements.
Finished Zone 1
Finished Zone 2
Finished Zone 3
Finished Zone 4
Finished Zone 5
Watch the credits until the end
Kill 5 birds
Defeat 100 spiders
Defeat 50 chargers
Defeat 20 stingers
Defeat 10 squids
Defeat 10 floaters
Defeat 10 swarms
Defeat 100 swarmlings