Here is the full list of all 21 Zombie Gotchi achievements.
You have gotten a Boy!
You have gotten a Girl!
Didn't liked your Zombie?
It will survive you!
Still no sign of life!
Yay, Zombies get ill?
They looking friendly!
There is something in there!
Happy Happy Happy!
Looks like your Brain next!
You survived the Tutorial!
Best Hair Ever!
Delicious!
Do you remember?
Yummy, Bunny!
Let's battle!
Did you hit?
I can see living People!
Coming Home!
Did i meant "Alive"?
Snack Bubble!