Limbo Page

The Limbo Page is a hidden amount of data in the GOTY version of Plants vs. Zombies that contains ten mini-games, along with four variations on Survival: Endless, that were going to be added to the game, but were eventually cancelled. It is possible to access this page via using third-party memory editing programs such as Cheat Engine and changing specific data values. All Mini-games (with the notable exception of Ice Level) are fully playable.

Gain access to Limbo Page
Add three addresses and change all the value to 144.

See this video tutorial.

Another way
For the Game of the Year version
 * Open cheat engine
 * Click "Memory view"
 * Search for address "00430C80"
 * Select "Replace with code that does nothing"
 * Done! Enjoy those cancelled mini-games!

Video:Plants Vs. Zombies - Hidden Mini Games

List of games

 * Art Challenge Wall-nut: Place Wall-nuts in the proper spaces to create one giant Wall-nut.
 * Sunny Day: Here, everything is normal, but all Sun from the sky is 50 Sun instead of the normal 25.
 * Unsodded: Rows one and five cannot be planted on, but Zombies still appear in those rows.
 * Big Time: Here, Sunflowers, Marigolds and Wall-nuts are all twice their normal size.
 * Art Challenge Sunflower: Place plants in the proper position to create a large Sunflower.
 * Air Raid: A fog Level that has a very high amount of Balloon Zombies.
 * Ice Level: The Zombie Yeti is supposed to make an appearance on this broken level.
 * High Gravity: On this Roof level, very high Gravity causes Projectiles to only hit the tile in front of it. Balloon Zombie's Balloon pops after going a few tiles.
 * Grave Danger: Zombies surface from graves all during this Mini-game, and more graves appear frequently.
 * Can You Dig It? The Lawn is full of Wall-nuts and the only plant you can plant are Peashooters.
 * Dark Stormy Night: Basically like 4-10, but with different plants and Zombies.
 * Bungee Blitz: The same as 5-5 in Adventure Mode.
 * Intro: The beginning segment of the Game. Also puts you into Adventure Mode instantly.
 * Survival: Day through Roof Endless (Except Pool): The same as Survival: Endless, but inside the Day, Night, Fog, and Roof areas, respectively.
 * Upsell: Crazy Dave convinces the Player to upgrade to the Full version of Plants vs Zombies.
 * Squirrel: This hidden mini-game is about finding seven Squirrels by digging up Wall-nuts. Does not appear in the Limbo Page.

Trivia

 * Since the other game modes are shown on it and when another tab is clicked on it shows the three other pages, the Limbo Page may be a preliminary setup for the title page. However, the one we know is now used.
 * Squirrel is the only mini-game that doesn't appear on the Limbo Page.
 * The player must unlock Mini-games on Pool level 3-2 before they can use the Limbo Page. If they haven't reached that point in Adventure Mode, then the Limbo Page is inaccessible.
 * If there are any locked mini-games on the Mini-Games page, completing a game on the Limbo Page will unlock the next locked mini-game from the Mini-Games page.