From the campaign:
OST is the first in a dynamic series of fresh, tactical wargames. OST simulates, through an easily-learned game system, small unit engagements on the Eastern Front during 1941-42.
Two players contest each scenario using counters representing the soldiers, guns, and vehicles that fought these desperate battles. On each turn play goes back and forth between the sides as Impulse Points are spent to enable a player's forces to act. When the battle is over, casualty and victory points are tallied and a victor is declared.