Requirements:
Firefox/Chrome
Cheat Engine 6.0

Steps:

1. Enter Millionaire City [play now]
2. Open Cheat Engine
3. Select browser in process list (plugin.container.exe for firefox, 3rd chrome.exe for chrome)
4. Scan 55000000 (This is for Super Skyscraper. )
5. 1 address returned. Ends with 4C
6. Change 4C to 14
7. Notice value changes to 55. Which is the min level required to be able to purchase Super Skyscraper.
8. Change the value to 1.
9. Repeat steps 4-8 for other buildings. Click on the image above to see the value to scan.
10. All the addresses will end with 4C. Just change them to 14. For certain buildings with more than 1 addresses, just look at the value. Example, you scan 110000000, change all the 4C to 14 and the one with value 60 will be the one you want to change to 1. Simple yea?

Building Code:

Super Skyscraper - 55000000
Skyscraper Ultimate - 110000000
Highland Castle - 100000000
Brazilian Skyscraper - 250000000