Here is the full list of all 14 A Gummy's Life achievements worth 1,000 gamerscore.
Unlock Burger
Unlock Cherry
Unlock Skull
Earn 50 points in any game mode
Earn 100 points in any game mode
Earn 300 points in any game mode
Earn 1000 points in any game mode
Kill a gummy using the tractor
Wax on, wax off
Kill 10 gummies in any game mode
Kill 100 gummies in any game mode
Kill 1000 gummies in any game mode
Kill 10000 gummies in any game mode
There are never too few zombies