Here is the full list of all 11 TowersRTS achievements.
The base game contains 8 achievements, and there is 1 DLC pack containing 3 achievements.
Win Path of Electricity on hard without losing a unit to a lightning
Win Gloomy Harvest on hard without losing a unit to a plant
Win wildfire on hard without losing a unit to the fire
Win 100 Multiplayer Matches
Win 50 Multiplayer Matches
Win 25 Multiplayer Matches
Win a multiplayer match without losing your Hero
Finish the tutorial island
Upgrade 400 times your buildings
Upgrade 200 times your buildings
Upgrade 100 times your buildings