Here is the full list of all 36 Defendion achievements.
Buy icewall
Complete the tutorial
Win. Once.
Buy cannon
Buy wall
Buy firewall
Defeat once
Complete 10 waves
Make her speak
Collect 1000 gold
Win minesweeper
Kill 100 enemies with cannon
Kill 100 enemies with arrows
Kill 100 enemies with fire
Freeze 100 enemies
Kill 50 enemies with ballista
Kill 1000 enemies
Change captive's clothes
Win dice game
Complete Castle level
Complete Forest level
Complete Road to Arena level
Complete Arena level
Complete Road to Magic level
Complete Mage Village level
Upgrade Cannon Tower to 5 lvl
Upgrade Arrowed Tower to 5 lvl
Upgrade Flaming Tower to 5 lvl
Upgrade Freezing Tower to 5 lvl
Upgrade Ballista Tower to 5 lvl
Upgrade Castle to 5 lvl