In HeroQuest, one single critical roll does not end a contest. In RuneQuest it might. This option is present in BRP - but BRP has one more success level, the special success - at a cost in Magic Points, and I will use it heavily in BRP Mecha. But in that case we are speaking of 60mm gatling guns or energy weapons that can blow up a battleship, so the players must have a way to avoid the effects of a critical hit.