Command and Conquer

Once your in a game a few simple buttons will mean the difference between a victory and a defeat.First,at the title screen enter the barracuda(B,A,R,R,A,C-RIGHT,UP,DOWN and A).
Then once you're in a game simply press L,R,and UP,and the mission will be a success.If you press L,R and DOWN you're mission will be a failure.

All Levels:
At the screen where it says press start at thre beginning screen press b,a,r,r,a,c-right,up,down,a! after that goto replay mission and press L you should get all levels!
 
Cheat mode:
At the title screen, press B, A, R(x2), A, C-Right, Up, Down, A. Then select the "Replay Mission" option at the main menu, you will then be able to press L to display all missions and R to select your team.
If you then start your battle after inputting the code you will be able to press R+L+Up to win and R+L+Down to lose. You can also press R+L to display debug information.