Below are the tips of the selected levels.

LEVEL 1 | Arena + Conveyor

Best perk: Cherry Picker Perk

Quite difficult to complete both Bonus Objectives for low-lvl plants.

LEVEL 2 | Conveyor

Place a Shrinking Violet on a power tile, apply plant food to shrink all zombies on the lawn.

LEVEL 3 | Perk Grind

Best perk: Chill Zombies perk

Quite easy level even for low-lvl plants.

Use Primal Peashooter / Draftodil for stun zombies objective.

Use Imp Pear / Chilli Bean to handle ZCorp Consultant.

Beware of Octo and Surfer Zombie.

LEVEL 4 | Conveyor | Perk Grind

Best perk: Cherry Picker Perk / Jalapeno Pepper Perk

Very easy conveyor level given that Grapeshot can one-shot kill most of the zombies in this level.

Strategy: Split the lawn into upper and lower part. Focus each part with Grapeshot and Chilli Bean respectively.

LEVEL 5 | Conveyor

Best perk: Cherry Picker Perk / Jalapeno Pepper Perk (Lvl 3+)

Place Wall-nut on 2 minecarts at C6 to block Zombie Bull.

ZOMBOSS | Zombot War Wagon - Wild West + Lost City

Zombie level: Lvl 1 / 4 / 7

Zomboss health bar: 5 / 7 / 9

Seed slot: 7 / 6 / 5

Locked plant: SeaFora

Best perk: Jalapeno Pepper Perk

Sun production is optional because there are a lot of suns dropping from the sky. There are also pre-planted Gold Tile.

Lightning Reed / Power Vine / Spear-mint can effectively handle Zombie Chickens.

Especially thanks for Youtube UP : Darren-G