Here is the full list of all 19 Ben and Ed achievements.
Kill 100 chicken.
Kill 50 chicken.
Finish the game.
Beat all level unharmed.
Reunite with your friend.
Beat Hans.
Impress 700 viewers.
Beat Hans' second masterpiece.
Collect 50% of all candymeat.
Kill 20 chicken.
Beat 12 level unharmed.
Collect 20% of all candymeat.
Impress 200 viewers.
Beat 5 level unharmed.
Beat Hans' first masterpiece.
Reach a checkpoint in one piece.
Finish the tutorial.
Collect 100% of all candymeat.
Impress 1100 viewers.