Here is the full list of all 27 Super Sanctum TD achievements.
Have no blocks at the end of a level.
Hit 10 enemies with Thunderbolt.
Kill a Walker with an Anti Air Tower.
Beat a level on Hard.
Beat a wave with only skills and blocks.
Beat all levels on Normal.
Clear Elysion
Kill the Patriarch.
Clear Brightholme Industries.
Kill a Huge Walker.
Kill the Charger and all its clones.
Unlock all towers and skills.
Clear the Hydro Islands.
Unlock all tower and skill slots.
Get 100 perfect rounds.
Kill 10 enemies with a single shot
Kill a Big Walker.
Clear the Facility Compound
Kill 2 enemies with a single Bomb.
Complete a level without using any skills.
Clear the Training Area.
Complete one level.
Kill 10 enemies in a single Penentrator shot.
Beat all levels on Hard.
Kill the golden Walker.
Get all stars in all levels on Hard difficulty.
Kill 10.000 Walkers.