Contra is a freeware modification for Command and Conquer Generals: Zero Hour real-time strategy game. It's a big project started in 2004. It adds many new units as well as numerous new upgrades, new general's powers and buildings. It also adds new sounds, maps, bug fixes, enhanced graphics, and other effects, as well as three new generals.
My biggest achievement at map creating so far. This AOD has 3 modes: Easy, Normal and Insane. Easy and Normal both have same waves you just start with a different money value. Insane on the other hand is using entirely new waves and you are starting with $10000. Insane also has a special ending in this AOD, it's very similar to the General Challenge.
If you are having trouble installing the map, you can find a document in the .zip.
There you will find all the information you need... hopefully.