Here is the full list of all 20 Age of Steel: Recharge achievements.
Buy all levels in Survival mode
Complete campaign
Complete Act IV
Buy 7 levels in Survival mode
Complete Act III
Buy level in Survival mode
Complete Act II
Earn 100,000 resources
Destroy 1000 enemy units per session in Survival mode
Earn 50,000 resources
Destroy 500 enemy units per session in Survival mode
Destroy 100 enemy ships
Destroy 100 enemy units per session in Survival mode
Earn 10,000 resources
Build a 12 walls at the same time
Destroy 100 enemy aircraft units
Improve your base to the maximum level
Complete Act I
Destroy 100 enemy ground units
Complete level Hilltown