In the original Call of Duty, two missions of the Russian campaign involve the player commanding a T-34-85 Medium Tank (mentioned in the level's introduction letter) and engaging German armor through open country and a bombed-out town. The in-game tank also had a hull mounted machine gun that automatically fired whenever there was infantry in front of the tank.
The tank is tasked with destroying Panzer tanks. One well aimed hit to the turret will usually knock out an enemy tank.
In Call of Duty: United Offensive, the T-34-85 is the medium tank usable by the Russians. It has a cannon and an SG-43 machine gun on its top. There is room for two players in the tank; one being the driver and the other manning the SG-43. The cannon has good accuracy and can hit targets at medium range. It's a well balanced tank that, while not too fast, will easily knock out enemies. Just remember to time the shots correctly.
In Call of Duty: Finest Hour the player commands a T-34 on four different levels. The turret of the tank features a machine gun. The aim on the T-34/76's gun is actually off by a few degrees, with the shell curving to the left of the crosshair, as seen at extremely long ranges.
In Call of Duty: World at War, the T-34-85 is shown throughout the Russian campaign. The player controls it in the level "Blood and Iron" where the co-axial machine gun has been replaced by a flamethrower (thus making it an OT-34-85, or a flame tank). In the mission "Ring of Steel", the player can use the tank's machine gun. On certain multiplayer maps, the player can control T-34 tanks which can be manned by two people; one being the driver and the other being gunner for the mounted machine gun. The T-34 that the player controls during "Blood and Iron" is equipped with wire mesh stand-off screens to protect thinner side and top armor from HEAT warheads such as those fired by the GermanPanzerfaust. The T-34 also appears to be equipped with stand-off screens. However, the multiplayer T-34 uses an upgraded form of stand-off screen.