On p. 159-60 of the Rulebook:
Any successful Melee or Ranged Test that also rolls a double causes a Critical. This means you have dealt a significant blow, and it even happens when you are the defender in an opposed Test.
If you score a Critical, your opponent receives an immediate Critical Wound as your weapon strikes true. See page 172 for more on what this means. Beyond that, SL is calculated as normal, as is who wins any Opposed Tests.
My understanding of this is that, RAW, even if a combatant loses their Opposed Melee Test, but rolls a critical, the “opponent receives an immediate Critical Wound as your weapon strikes true.” So, for example:
Alice, human soldier with Melee (Basic) 45, is being attacked by a goblin, WS 25. The goblin rolls 11, and so has SL +1 and a Critical. Alice uses her Shield (2) with Melee (Basic) to oppose the attack and rolls 15, and so with SL +3, wins the Opposed Melee Test and successfully defends. However, because of his Critical, the goblin proceeds to roll on the Critical Table for a Critical Hit, doing not just wounds but potentially permanent damage or death to Alice regardless.
This resolution to the combat seems counter-intuitive to me. Of course, I understand that combat and wounds are intentionally perilous in WFRP. However, this example just doesn’t make narrative sense to me, and I feel like I’m missing something.
Does the loser of an Opposed Melee Test make Critical Hits against the winner?