OpenRA

OpenRA is an open-source engine that revives the classic real-time strategy games from the Command & Conquer family. It includes mods that recreate Red Alert, Tiberian Dawn and Dune 2000 with modern conveniences: higher resolutions, better pathfinding, online multiplayer and replays.

The interface is closer to modern RTS games, with features such as queueing production, control groups and a clear minimap, while the units and factions keep their classic feel. Skirmishes against bots, missions and online matches are all available, and the community maintains additional mods.

OpenRA is free software under the GPL, with no ads and no purchases. Some mods may ask to download extra content the first time you start them.