When installing OpenRA, it must be stressed that it isn't a video game but the foundation that supports others. You can automatically download a review of Command and Conquer: Red Alert. From that point, you can start playing in solo mode (against the AI) or against players from around the world online.
The main new feature that OpenRA brings, in relation to the classic Command and Conquers, is that the graphics have been adjusted to the most current resolutions and support panoramic screens. Thanks to this, you can enjoy real-time strategy from the 90s with fantastic visuals that still look good today.
Apart from this, the thing that makes OpenRA so special is that you can add different mods really easily. For example, the official modding forum has over 100 different threads where users share their work, and some of these modifications to the game base let you experience practically new games.
OpenRA is possibly the best way of enjoying the classic Command and Conquer games today. It is a true gift for traditional real-time strategy fans where they can find hours and hours of fun.