2 more old games that might not have made the list. Myth 2 and KKnD.

[Ambiguous64]

2 tough games from the way back when, in the late 90's. Myth was made by a young Bungie, before it was known as the name behind the FPS series Halo it made an RTS game without resources. The units you start each map with, are all you get, so use them wisely. Also Dwarfs with grenades who are both your best friend and worst enemy as friendly fire is very much a thing in this game. And with Dwarfs comes both great power and great responsibility. 

As for KKnD, or Krush Kill and Destroy, it's also an RTS game, set in what I can only think of as the Mad Max style world. Two societies have risen from the aftermath of the apocalypse, one normie humans who survived underground called The Survivors, and one a society of mutants called The Evolved who managed to live above ground. Both hate each other and go to great lengths remove the other. The best part though to be the scenes the precede every level. A lot of time was spent on the voice actors, and it Rivals Red Alert's scenes. 

Some quick links for the curious. 

KKND -  

 
Myth 2 

I hear Myth (1) was good too, but I never had the chance to play it. 

[Alyxx Thorne]

I heard about KKND from magazine demo discs back in the day. But don't hear it talked about a lot, so it's gotten fairly obscure indeed.

[biosynth8]

Hah, both of them drove my brother half insane with their difficulty. I think he broke a keyboard over Myth 2.

KKND is really a blast with the FMV scenes. It's on GOG, too.

Myth was truly ahead of it's time and there are few games like it, even today.