Here is the full list of all 20 Hydraulic Empire achievements.
You have completed Level 1
You have completed Level 5
You have completed Level 8
You have completed Level 11
You have Completed Level 14
Beat level 1 without building any towers. This must be done on atleast Medium Difficulty
Beat level 5 without allowing any enemies to get to a waypoint. This must be done on atleast Medium Difficulty
You have Completed Level 17
Kill 100 bots with your Keeper in a single level. This must be done on atleast Medium Difficulty.
Beat all levels on Normal or Above.
Beat all levels on Hard
Keeper has reached level 15.
Keeper has reached level 20.
Keeper has reached max level.
Fill all the slots of your city.
Fill all the slots of your factory.
Get a level 6 tower.
Kill a mob in the final hex, and beat the level. This must be done on atleast Medium Difficulty.
Do not allow Swarmies to spawn in a level that has Swarm Mothers, and beat the level. This must be done on atleast Medium Difficulty.
You have Completed Level 21