The Model 89 appears in several missions, usually on a high position such as on top of a hill. It is capable of inflicting the same amount of damage as a Kiska grenade, and can be very dangerous if the player is charging against it. The weapon is unusable by the player.
Some Allied soldiers nicknamed the Model 89 the Knee Mortar, due to the common misconception that the user would have to fire it while holding the weapon on his lap. In reality, the mortar did in fact come with a base plate, and those American soldiers who attempted to fire the weapon while holding it usually ended up with serious injuries.