Stronghold Crusader. A brilliant castle-building RTS. Todays Deal of the Day on GOG. (includes "extreme" addon, but does have the usual GOG extras - Manual, Soundtrack, wallpapers and also a minigame.)
Cheaper than the previous download price on Steam ~5-6quid.
Works in Windows 7 fine (Inc 64bit)
What's cool about it:
Join the Crusaders and Saladin’s forces in four historical campaigns
Fight in 50 skirmishes, each one more challenging than the last
Use new units like assassins and mercenary soldiers to your advantage
Journey to distant Arabian lands renowned for brave warriors and fearsome weaponry in FireFly Studios' Stronghold Crusader. This highly anticipated successor to the best-selling Stronghold combines the finest aspects of a City Builder and RTS. Lead a determined group of Crusaders, forged by centuries of barbaric foreign invader amidst the haze of the desert heat.
Now you have the chance to relive the historic Crusades in four campaigns as Richard the Lionheart and Saladin, the Sultan of Syria. Attack the strongholds of fierce rival lords during the intense new "Crusader Mode". Conquer the "Crusader Trail" - 50 linked skirmish missions, each one more challenging than the last! Storm enemy barricades with over 25 units!
Create an awe inspiring fortress in the Castle Builder mode! Design challenging new scenarios with the full-featured map and scenario editor! Join for the ultimate crusade for the crown! Crush up to 8 friends in multiplayer Skirmish Mode via LAN or over the Internet!