I concur with Big Alba on the point that DR was incredibly difficult. In general, all it took to beat any other RTS game was to figure out the loophole in the computer opponent's "thinking". Your computer enemy invariably had a useless attack plan or a defensive Achilles heel the size of antarctica at the back of their base. Once you figured out what the computer was doing badly, you could figure out how to exploit it, and it's all over quicker than you can say "checkmate".
My experience of Dark Reign was a big nasty surprise. I was utterly unprepared for three-pronged attacks from a fully developed base while I was still setting up! It's just not cricket. In DR, the computer wages war to win, not to give you a fair chance at whooping his CPU ass.
Dismayed, I did some reading on the AI engine of DR. Impressively, the computer opponent in this game is capable of:
Assessing the level of risk your forces present
Assessing the ability of its own forces to eliminate that risk
If incapable of eliminating the threat, the computer will construct additional units until the force is deemed sufficient, doing whatever resource collection and building whatever infrastructure is necessary to carry this out.
If attempts to eliminate the human player with a simple direct strike do not succeed then the computer will attack from several different directions at once.
This is scary. Coming from games where the computer was there as a token resistance, I was up against a computer who was better at playing the game than I was. What an ego deflation.
You've gotta hand it to the people that put this AI together. Quite simply, it rocks.
Some other noteworthy things about DR:
Your ability to control the AI of your own units is damn fine. You can decide to what extent a unit will act independently, how far it will pursue fleeing enemy units and even (I love this bit) if you want the unit to seek a repair station when it gets seriously damaged. You can order units to travel a series of waypoints, save the route as a "path", and then order other units to use that path. This is a fantastic feature and I wish more games would pick it up.
Unfortunately, the interface did not live up to the intelligence of the units and the level of sophistication built into the terrain. I found controlling my units during battles quite a hassle and the very clever line-of-sight engine ended up being more of a nuisance than a cool feature.
To the credit of the game developers, Dark Reign had a good story. A decent plot and background is an important game aspect often neglected by developers.
All up, I'd say that DR sets a lot of new standards in game development, but it seems like they put too much time into making it a technically brilliant RTS and not enough into making it fun. After all, it is a game.