The following trick can be used on the Destroy Chemical Tanks GDI mission. Position an engineer next to the NOD ore processor and wait for the mining vehicle to dock with the structure before capturing it. Doing this will give you control of the building and the vehicle.
If you have the original unpatched game you can do the following trick to get a fully charged Firestorm Wall to last indefinitely without having to turn it off to recharge. Fully charge your Firestorm Wall and turn it on. Then before it turns off or runs out of power, sell or turn off your power plants until the message 'On Hold' appears in the Firestorm Icon. Your Firestorm Wall will now remain on indefinitely unless you build or turn on your power plants.
Start construction on whatever structure you want. I would advise starting with something small, like lasers or component towers. Once construction is complete, choose the area you wish to build. It must be open ground or it won't work. Doesn't matter if it is revealed or not.
Move around on the map until the structure on the menu is just to the left of the area you want to build on. "Don't select it".
Now align your cursor with the structure and have the cursor half on the playing field and half on the power bar, in alignment with the structure you're going to place.
Press and hold the right mouse button and quickly move the cursor to the structure on your menu and left click on the structure with the right mouse button still held down. You must be quick about this because you will start to scroll across the map as soon as the cursor leaves the playing field. Be careful not to release the right mouse button as sometimes this will cancel the build and you'll have to start construction on it all over again.
There you have it. If it doesn't build, the area either isn't clear or you released the right mouse button before you hit the left mouse button. If not, move your cursor back into the playing field and deselect the structure and try a different spot. Structure has to be ready, but not selected.
If you have trouble with this, don't get discouraged. Keep trying and you will soon master this cheat.
This cheat was written Exclusively for SuperCheats by evilxx.