Here is the full list of all 17 3rd Invasion - there are Zombies vs Steel achievements.
Just Start the Game
Win Any Battle
Meet the Zombies for the first time
Fight the Plant for the First time
Fight the Aliens for the First Time
Find the Alien Base
Kill All the Areas With Plants
Defeat All the Areas with Aliens
Defeat every Area With Zombies
Battle Each of the Enemies
Contiunal play for 15 Minutes
Contiunal play for 30 Minutes
Contiunal play for 1 Hour
Win 10 Battles
Win 20 Battles
Look at the LeaderBoard...
Having Money is important.