Here is the full list of all 50 GAIA 2200 achievements.
Kill 1 enemy
Kill 1000 enemies
Kill 10000 enemies
Upgrade 1 tech to full level
Upgrade 3 techs to full level
Upgrade 5 techs to full level
Unlock 1 hero
Unlock 3 heroes
Unlock 6 heroes
Upgrade 1 hero to full level
Upgrade 3 heroes to full level
Upgrade 6 heroes to full level
Unlock 2 spell cards
Unlock 7 spell cards
Unlock 15 spell cards
Unlock 30 spell cards
Cast 10 spells
Cast 50 spells
Cast 100 spells
Cast 500 spells
Gain 500 exploration points
Gain 1000 exploration points
Gain 5000 exploration points
Gain 10000 exploration points
Unlock 5 monsters in manual
Unlock 15 monsters in manual
Unlock 21 monsters in manual
Beat 1 N-bomb Scrapcar
Beat 1 King Rat
Beat 1 Mother Mermaid
Beat 1 Boss Crab
Beat 1 Radiation Variationman
Burn 100 enemies
Freeze 100 enemies
Poison 100 enemies
Kill 100 enemies by heroes
Heroes die 10 times
Play slot machine 100 times
Tap 1000 times in Tap Mode
Gain 100 cards in Conveyor Mode
Change location of heroes 100 times
Survive 180sec in Endless Mode
Restore 1000 Hp to heroes
Restore 1000 Hp to the Spacecraft
Cast 50 spells in one battle
Win a battle with 1 Hp
Burn,freeze,poison an enemy at once
Unlock 15 Junior Medals
Unlock 15 Advanced Medals
Unlock 15 Master Medals