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. There are lots of people playing in multiplayer.
Cyber Dog is fully mechanical, and produced in Barracks. It is very fast, and because of this, is mostly used as infantry hunter. With its sharp iron teeth, it rips enemy infantry into pieces with one bite. You can use it in early game to block tech structures from being captured by your enemy. It is very effective vs. GLA generals. Due to its mechanical body, machine guns cannot harm it seriously. But RPGs and all other armor-piercing weapons can kill it almost instantly. Since it is a pure robot, it is vulnerable to ECM. Can be upgraded with Exoskeletons and Advanced Data Transmission upgrades.