Infinite Firestorm Wall
If you have a firestorm wall and it is fully charged, you can make it last forever without having to turn it off to charge. First charge your wall fully, then turn it on. Before it turns off or runs out of power sell or turn off your power plants until the words "On Hold" appear in the firestorm Icon. Your wall will stay on forever and will not run out of power until you build or turn on your power plants.
Level 9 Hint
At this moment the most asked question is: "How do I get behind the lasercannon ( The Obelisk of light )". Well, at the right of the cannon there is a small base with a 'hand of NOD' building and a few powerplants. First of all you must destroy the units on that base. After that, destroy all the powerplants so that the NOD has low power. Then you can pass the lasercannon or you can destroy it. When you go to the top of the map there is a base you can capture. Capture it and destroy all NOD units.