Spend all of your money for a year. When the Tax Screen appears at the end of the year, hold L. While this button, return to the main game and press X(2) to display the tax screen again and advance the month to January. The text "GO WITH FIGURES" will be replaced with "GRO WITH FIGURES" to confirm correct code entry. Increase all funding levels to 100%, exit the screen, and release L. Your account balance will be $999,999.
Bonus Casions and Theme Parks
Choose a landscape that is not an island, but has a large amount of water. There should be a body of water towards the middle of the landscape. Create roads in a way to form a cross near the middle of the landscape, near the water. The roads must continue until reaching the edge of the map. Two to five casinos or amusement parks may now be built.
Change Landscape
Start with a new city, select any landscape, and wait at least ten seconds. Enter the total screen. Exit the total screen, enter the save/load menu, then select the "No" option. Return to the main menu, select the "Start New City" option, and the landscape will change. This effectively doubles the amount of maps.
Debug Mode
Warning: Using this code will delete your saved games. Wait until the city appears during the opening sequence. Hold L + R + Select and press Up(3), Left, Up, Down, Left, Up, Down, Right(2), Left, Up(2), Down(2). A sound will confirm correct code entry. The debug icon will appear on the menu when game play begins.
Erase all saved data
Press L + R + Select.
Get away with not paying funds
Auto-Budget must be off to use this code. When the Budget screen comes up at the end of the year, set all funds to 0%. Now select Go With Figures. Immediately save the game, then reload it. The game should continue as if you set all funds to 100%, but you weren't charged for them on the budget.
Stop the meltdown from happening in the Boston scenario
Before you start the Boston 2010 scenario (at the telefax screen,) immediately hold the L button before you start. Keep holding the L button, and then bulldoze the three nuclear power plants. After you have bulldozed them, release the L button and rebuild the three plants. Now you can play the scenario without the meltdown actually occurring.
Tokyo Scenario
Before you start the Tokyo 1961 scenario (at the telefax screen,) immediately hold the L button before you start. Keep holding the L button, and then bulldoze every square of shoreline. After you have bulldozed them, release the L button. Now you can play the scenario without the flood actually occurring.
$999 999...