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