Stronghold Crusader on steroids.
For those who have never experienced Stronghold Crusader, it's a real time strategy game with heavy emphasis on castle building and sieging. Buildings (Farm, Food Processing and Industry) are constructed instantly if you have the required resources, so your main task is making sure you have enough willing workers to take on the required jobs. This is done by keeping your people happy, which in turn hinges on keeping them well fed and not taxing them too heavily. Meanwhile there's your castle to build and defenses to install, soldiers to train and siege engines to build and send forth against your enemies' fortifications.

The key is to keep everything in balance: if too many of your alloted units are trained as soldiers, you won't have enough workers to gather resources and produce weapons. If you don't have enough soldiers, you run the risk of being overrun by the enemy. Tax too lightly and you run out of money, tax too heavily and your unhappy populace deserts you. Build too much housing to increase your maximum allowed units, and you risk emptying your granary. Like I said, a balance.

That's the vanilla Stronghold Crusader. Now let us turn our attention to Stronghold Crusader Extreme, the cranked up, tricked out, er... extreme version of Crusader. 5 (Extreme) new AI Opponents. 30 stand-alone maps, and 20 new Missions (presumably all Extreme). 10,000+ units on the battlefield at once! Extreme!! Extremely eye-watering, that is, unless you enjoy watching hundreds or thousands of sprites cycling through their half-dozen frames of animation in synchrony.
That's correct, there have been no graphical updates to this game which already looked dated when it first came out six years ago. Excited yet? How about Outposts “filled with hordes of attacking enemies”? Not good enough? Try on the Tactical Powers for size: 8 special abilities that allow you to reinforce or heal your troops, or annihilate the enemy, with a couple clicks of the the mouse. Simply put, they rip the guts right out of the game.