Your troops are in dark clothes, moving from left to right. Cover them! Eliminate enemy soldiers in light camouflage. Choose your weapon...rapid fire 25mm? Tank-busting 40mm rounds? Or maybe you like to carry a big stick, like a 105!
mouse to aim; left button to shoot; scroll to change guns (A = 105mm, S = 40mm, D = 25mm) U/D to toggle guns; space bar for menu.