Here is the full list of all 36 Tanks vs Aliens achievements.
Don't lose tanks in Level 2
Complete Level 5 with (с)200 or more
Prevent turret from getting damaged in Level 3
Create 6 or more tanks in Level 1
Meet K.O.R.B.
Meet Talira
Complete Level 4 without upgrading your tanks above level 2
Destroy enemy Nomad before getting reinforcements in Level 6
Complete Level 7 before wave 5 begins
Complete Level 8 in 8 minutes or faster
Complete Level 9 repairing your tanks 10 times or fewer
Complete Level 10 using no Snipers
Complete Level 11 in 8 minutes or faster
Complete Level 12 using only Barbarians
Complete Level 13 in 9 minutes or faster without losing a tank
Complete Level 14 before wave 5 begins
Lose fewer than 5 tanks while completing Level 15
Don't lose mining towers while completing Level 16
Complete Level 17 with (с)1000 or more
Complete Level 18 creating 12 tanks or fewer
Destroy enemy base in Level 19, capturing only first point
Complete Level 20 without upgrading tanks
Complete Level 21 with (с)2500 or more
Complete Level 22 using no Paladins
Save all hostages using no more than one Paladin in Level 23
Save the Barbarian in Level 24
Complete Level 25 without losing a tank
Destroy enemy base in Level 26, capturing only first point
Complete level 27 upgrading no more than 3 tanks
Complete level 28 without activating friendly tanks
Complete Level 29 without losing a tank
Complete Level 30 before all attack waves have ended
Meet Rogan
Complete the game in Bronze difficulty mode
Complete the game in Silver difficulty mode
Complete the game in Gold difficulty mode