These are even harder challenges and some contain luck.

Here they are:

Have a Jack-In-The-Box Zombie eat your brains

Get 1000 flags in vasebreaker endless

Clear pogo party without tall nuts or magnet shrooms(Sproing!Sproing achiment)

Fill The lawn with Winter Melons

Fill all Zen Gardens with one of each plant avalible

Hynotise Your Zombatar