Best of the series. Has aged very well.
Single player lasted me 27 hours this playthrough, which is quite a decent length. Most levels are the generic build a base while destroying all enemies from the map, but there are also other types. Some of them you have no base, and a set number of troops. You have an objective to get to on the map, and have to find the best path where you can free some of your soldiers from the enemy while avoiding as much enemies as possible, since you have no reinforcements.
The 2 factions are very well balanced. I found that in later C&C games, the faction units went a little overboard, and I enjoy the balanced simplicity of this game. Don't take this the wrong way though. I don't mean to say that there are very standard boring units.
Within the single player campaign I found there were a couple good strategies to win. One was to build alot of fighter jets, and overwhelm the enemies air defense. After that their base is easy picking with those jets. You could also tank rush, but I most often preferred a strong airforce. Now I am rambling.
Bottom line: Anyone who plays games for gameplay over graphics, check out this classic RTS. It has aged well and the controls make sense. There is very little to complain about.