In Allied Assault and it's expansions, the Mark II grenade appears on all missions as a starter weapon that cannot be replenished. The grenade can be cooked for several seconds before throwing it. Also is the default grenade for Americans in multiplayer.
Mark II Fragmentation Grenade in Medal of Honor: Allied Assault
Mark II is an additional weapon if the player has Thompson (which is the starting weapon on all missions) or BAR. It deals huge damage to the enemy if the grenade is exploded close to him, and knocks down if the explosion was close. The grenade can also be used in the first-person levels "Covering Fire", "Unexpected Party" and "Shoot Out". They are capable of one hit to destroy a soldier or equipment.
In Medal of Honor: Pacific Assault the Mark II is the standard issued grenade for the Marines. The Mark II has a distinctive yellow colour in-game which indicates that it is a live fragmentation grenade. During the boot camp mission the training variant of the Mark II can be used, but it has a dark green colour.
Mark II Grenade in Medal of Honor: Pacific Assault.
The Mark II grenade returns in Medal of Honor: European Assault as one of the three grenades in game. The player gain access to them in the Battle of the Bulge campaign. It functions as the same as the Stielhandgranate.
Mark II Fragmentation Grenade in Medal of Honor: European Assault
In Vanguard the Mark II is the only grenade available for the player in the single player. It is also the default grenade for the allies in split-screen. The Mark II functions same as it's European Assault counterpart.
Mark II Fragmentation Grenade in Medal of Honor: Vanguard.
The Mark II returns in both games as the default grenade for the player. In both games it is one of the three starting weapons. The player always start with 2 Mark II grenades. It is also the default grenade for the allied soldiers in both games' multiplayer. Just like it's earlier counterparts, the Mark II is best used to flush out enemies from behind cover. Performance wise it is the same as in European Assault and Vanguard.
In Medal of Honor: Airborne the Mark II grenade is powerful, with a large lethality radius, and can be cooked and thrown by hand or launched from a Rifle Grenade Launcher. It is not as powerful as the Model 24 Stielhandgranate, doing 100 less damage, and has a smaller lethality radius, at 650 in-game units as opposed to the M24's 750.
German soldiers caught in the way of a grenade usually flee as soon as possible, while some may kick or throw it back at the player. Occasionally, a German soldier may fall on the grenade to save his friends, but is killed in the process.