Tem como alguém adaptar para o TFS 0.4?
 
local config = {
    magic_effect = 15, -- magic effect you want to send when critical hit lands
    damage_multiplier = 10 -- default damage * 10 = critical damage
}
function onHealthChange(creature, attacker, primaryDamage, primaryType, secondaryDamage, secondaryType, origin)
    if attacker == nil then
        return primaryDamage, primaryType, secondaryDamage, secondaryType
    end
 
    if not attacker:isPlayer() then
        return primaryDamage, primaryType, secondaryDamage, secondaryType
    end
 
    local skill = attacker:getEffectiveSkillLevel(SKILL_SWORD)
    local chance = (skill * 0.1)
 
    if math.random(100) <= chance then
        attacker:getPosition():sendMagicEffect(config.magic_effect)
        return primaryDamage * config.damage_multiplier, primaryType, secondaryDamage, secondaryType
    end
     
    return primaryDamage, primaryType, secondaryDamage, secondaryType
end