The Tomb Raiser Zombies were the biggest threat, almost requiring higher-level plants.
Strategy
The player was almost forced to upgrade their plants' level by either replaying previous levels or by using Puzzle Pieces and the Oven in the player's house.
It was also recommended to drag as many plants as they could onto the lawn. Using other users' plants would have given even more power.
Gallery
Level layout
PvZ Online - Adventure Mode - Battle of the Nile 1