Steps:

Go to Cityville 2
Open Cheat Engine
Select -plugin_container.exe (firefox) or 2nd FlashPlayerPlugin_11.exe, if chrome you will 4.need to select the correct chrome.exe process.
Value Type '4 Bytes' to 'double'
Scan your current amount of population
Click the 1st address, Hold Shift and then click the last address.
Click on the red arrow.
Change all the values to "9999999" (TIPS: Select 1 address below. Hold Ctrl +A and then hit Enter key)
Buy a house (your population in shop will change)
Next, Go to MARKET > Decoration and buy a lot of Swing Set, Put it on the ground and then click Big X
Reload Game
After refresh, you population will become 9999999
HAVE FUN!!