Here is the full list of all 23 No Creeps Were Harmed TD achievements.
Destroy a Gleep container before the map wave goal
Complete one map
Complete a time bonus sub-objective
Complete the kill-all-creeps sub-objective
Use one of Brian’s special abilities.
Upgrade a turret
Get a level-up
Open the “How To Play” menu and learn stuff
Complete five maps
Complete ten maps
Complete fifteen maps
Complete twenty maps
Fail a map
Let Brian Jar die!
Get five levels deep into endless mode
Order Brian Jar to move
Configure a turret by changing its targeting priority
Sell an Artifact
Play with a friend
Get ten level-ups
Get fifty level-ups
Rush a wave
Complete 42 maps