Here is the full list of all 23 Ben and Ed - there are Blood Party achievements.
Cut off 1000 parts of your enemies.
Produce 1000 meatblocks.
Cut off 100 parts of your enemies.
Inject acid into 20 enemies.
Hold on to chickens for 30 minutes.
Hold on to chickens for 10 minutes.
Find Hans.
Produce 100 meatblocks.
Place 50 Trashcans.
Meet Ben.
Create Ed
Beat all singleplayer maps.
Finish the tutorial.
Build your own map.
Survive 60 minutes as head.
Produce 10 meatblocks.
Never give up!
Cut off 10 parts of your enemies.
Hold on to chickens for 1 minute.
Survive 10 minutes as head.
Finish a race headless.
Survive one minute as head.