Vietnam Glory Obscured is a total conversion of Command & Conquer Generals: Zero Hour. The game includes tutorial, skirmish, and multiplayer modes. There's only the USA faction to choose from, but more factions will follow with updates. The install is quick and made easy with an .exe file.
There are multiple units to choose from, and the combat mechanics use a Company of Heroes' battle system. It's better to attack with infantry and tanks instead of either unit alone. Most units are unlocked from the get—go, and more are available with general promotions.
The money system is like that of Zero Hour, but with a Company of Heroes twist where you take over villages and more to get additional money. A morale system also adds an additional source of funds and is based on the rebuilding or destruction of villages, the number of villagers killed in action, and more.
Although there's only one faction to choose from, you can be sure that more will follow with additional updates. Wait for those updates if you haven't bought the game just yet. For now, the skirmish and multiplayer capabilities give this mod a high replay value. You can check out this mod and many more at the GameSpot Downloads page.