Survival: Roof Night (Hard) Strategies

Get Survival: Roof (Night)
Can you beat this level? Show me!
 * 1) Go to Dr. Zomboss's Revenge, then quit after a while.
 * 2) Change the value to Whack a Zombie and kill every Zombie (including Zomboss) and collect sun.
 * 3) Then Change it to Survival: Roof or Survival: Roof (Hard).
 * 4) COMPLETE.