The original Sudden Strike, released in 2000, included three campaigns (Soviets, Germans, and Allied forces). The battles are presented in an isometric perspective with line-of-sight occlusions and practical cover. Sudden Strike helped pioneer the real-time tactics genre, building upon concepts established by Counter Action for DOS, which was published by Mindscape/SSI in 1996.
Sudden Strike utilizes accurate in-game physics with houses and buildings obstructing units' view, line-of-sight and firing range whereas clumps of trees can provide cover to reduce the damage of tank ordnance. The game allows units to garrison a building for a stronger firing position, especially valuable for anti-tank infantry. Units can also hold their fire, providing much-needed reconnaissance. Damage evaluation is also realistic; tanks or other vehicles that take too much damage are rendered immobile unless repairs are made.
Source: Wikipedia, Sudden Strike , available under the CC-BY-SA License.