The objective of this mini-game is relatively simple: you need to stop the zombies by launching corn cobs, but you can also temporarily stop zombies by placing butter on their heads. You can use your fingers in a smearing action on the touchscreen to immobilize large numbers of zombies, rather than tapping the heads of individual zombies. It is also worthless that if a Cob Cannon is eaten, it cannot be replaced, and there are no Lawn Mowers or Pool Cleaners to protect the area against the zombies that will inevitably get by.
The most difficult zombie to deal with on this level is Dolphin Rider Zombie, as it moves at high speed, and, as such, hard to stop with butter. Whenever a Gargantuar is less than halfway past the lawn, the player should not shoot a corn cob at it immediately, as it will throw its Imp. Instead, you should stun it with butter to prevent this from occurring. You can also stun its Imp before it eats a Cob Cannon. If the player still cannot beat this level, the player can use two people, instead of one (one person could control the Cob Cannon, one person could butter the zombies, etc.). The player can also fire two corn cobs at once and targeting the two land lanes closest to the pool so that zombies in an area in all rows will be hit.
Trivia
Buttered Popcorn is a pun on a snack with the same name.
For some reason, Buttered Popcorn is a Pool level, despite no aquatic plants being used, but this may be so that the player can only have four Cob Cannons at a time, or so Dolphin Rider Zombies can appear, making the mini-game difficult.
This could also be so that the player couldn't earn the achievement Defcorn 5 instantly.
Buttered Popcorn is the first mini-game exclusive to a particular version of the game.
Strangely, the achievement Pool's Closed cannot be unlocked by winning this mini-game.
On the Android version, the mini-game's description is using Beghouled Twist's description.
Buttered Popcorn is only one of two mini-games without a plant selection screen that lets the player use upgrade plants, the other being Air Raid. Both mini-games are also version-exclusive.
In the free iOS version of Plants vs. Zombies, there is a glitch where the player can have 50 sun at the start of the level.