My immediate tasks on hand:
Upgrade air defenses to level 6
Upgrade walls to level 7 (~55% done)
Upgrade hog riders to level 3
Upgrade collectors to level 11
not quite done but getting there
You'll never be done
I'm guessing that the people who have quite literally beaten the game have been playing non-stop for years and purchased hundreds of dollars in gems. I know what you mean though.