Here is the full list of all 21 Alien Shooter TD achievements.
Mission earnings: 100000
Complete 5 different missions on any difficulty level.
Wipe out 1000 aliens.
Mission earnings: 10000
Complete 25 different missions on any difficulty level.
Complete 25 different missions on easy level, earning gold stars.
Complete 25 different missions on medium level, earning gold stars.
Complete 25 different missions on hard level, earning gold stars.
Wipe out 500000 aliens.
Complete 5 different missions on any difficulty level using only mines and explosives.
Complete 5 different missions on any difficulty level using only Tactical Forces.
Train any soldier up to level 30.
Recycle 100 weapons.
Equip all troops with rare, unique and legendary weapons. Standard weapon should not be equipped.
Mission earnings: 500000
Complete 5 different missions in an expert mode, earning gold shields.
Complete 25 dif1ferent missions in an expert mode, earning gold shields.
Complete 35 different missions in an expert mode, earning gold shields.
Complete 35 different missions on hard level, earning gold stars.
Kill the Boss in mission №35 on hard level of difficulty.
Kill the Boss in mission №40 on hard level of difficulty.