Contra is a freeware modification for Command and Conquer Generals: Zero Hour real-time strategy game and one of the first mods for this game. 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.
Let's be honest here: despite the system's originality, the whole thing with requiring a general's promotion to access advanced tech is ridiculous. Not only does it ruin the game's pacing, it also punishes players for using more aggressive and risky tactics - the tech advantages promotions grant are just too great, as soon as the player earns rank 3 or 5 they become a way bigger threat. This also means that minor defeats are even more painful than in other RTS games, as you not only waste time and resources spent on units/structures lost, you also help your enemy advance further in the tech tree. Please consider removing the promotion requirement feature, it ruins all the enjoyment you could receive from this mod.
Also, while the additions of more fantastic tech is a pretty welcome addition, even while that is subjective, I wish devs would attempt to make new custom stuff look more consistent with the vanilla assets, as palette/aesthetic differences are pretty clashing.
Oh, and balance is kinda questionable, but that's forgivable - the mod seems to be more centered around fun, not competitive play.
Overall it's a pretty great mod ruined by a pretty silly feature. Hope it gets removed or made optional eventually.