>>724036464
Other games can do vehicles I think, but the melee and grenades are only possible in Halo due to the high TTK. If your gun kills in under half a second then the only way to make melee and grenades not completely worthless is to make them instant kill. Even then melee is generally not good due to the limited range and with grenades also being AoE, in order to make them not overshadow normal guns or to encourage cheesy cross-kill strategies they often have a delay to throwing and/or detonating, which often makes them still bad for anything than tossing out over walls or the like into the vague area of the enemy spawn to get a lucky kill or in the very rare instance there's a hard-camper in your lobby.