Below are the tips for selected levels.

LEVEL 1 | Conveyor

Best perk: Quick Delivery Perk

A bit challenging to defeat 125 Roman Zombies for low-level plants.

Place Threepeater furthest to the right, followed by Torchwood and Witch Hazel.

Boost score: While Appease-mint is delivered through the conveyor belt, wait until the score multiplier reach at least x4 (preferably x5) before planting Appease-mint.

LEVEL 2 | Last Stand

Very difficult to complete both Bonus Objectives for low-level plants - limited sun, cannot lose plants, there are large hordes of zombies.

Note: Witch Hazel Plant Food can transform zombies into Toadstool to generate extra suns, however, Puff-shroom gets eaten by Zombies will be counted as losing a plant.

LEVEL 3 | Bulb Bowling

Best perk: Quick Delivery Perk

Spam Arma-mint, Arma-mint will be recycled in the conveyor belt.

Shovel is disabled, leave 1 tile for Arma-mint.

LEVEL 4

Impossible to complete the Bonus Objectives to electrocute zombies within given time - Fila-mint plants are quite weak at lower levels.

LEVEL 5 | Conveyor

Best perk: Bass Blast Perk

Focus on tiny zombies (Ice Weasels or Zombie Chickens) to complete the Bonus Objective to electrocute zombies.

Beware of ZCorp Consultant, she enters the lawn and eat your plants with lightning speed.

ZOMBOSS | Zombot Dark Dragon - Dark Ages (with ZCorpion + ZCorp Consultant, Extra Hot)

Zombie level: Lvl 1 / 4 / 7

Zomboss health bar: 5 / 7 / 9

Seed slot: 7 / 6 / 5

Locked plant: Power Lily

Best perk: Boost Tile Perk

Again, Appease-mint strategy is very effective in the Zomboss level - however, you need to bring a plant that can handle Jester Zombie such as Stickybomb Rice or Explode-o-Vine.

Sun production plant is optional if you bring Grave Buster/Tomb Tangler.