Here is the full list of all 987 Zombie Boom achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Get 60 Gold Medal
Get 55 Gold Medal
Get 50 Gold Medals
Get 45 Gold Medal
Get 40 Gold Medals
Get 35 Gold Medals
Get 30 Gold Medals
Get 25 Gold Medals
Get 20 Gold Medals
Destroy 1 more enemy
Get 15 Gold Medal
Get 5 Gold Medal
Get 1 Gold Medal