The “mace of smiting” states that it destroys a construct on a critical hit, but constructs are immune to critical hits. I presume this enchantment is meant to be an exception to the rule that constructs are immune to crits, but that raises other questions. If the mace wielder has the feat Improved Critical, does that improve the threat range to destroy a construct? What happens with other magical weapons with special effects on a critical hit? For example, does a “flaming burst longsword” burst for extra fire damage when you roll a critical vs. a creature immune to critical hits? Are critical immune creatures immune to the sonic burst from the “thundering” enchantment?
Smiting and disruption weapons use the critical rules for their special effects, even though undead and constructs cannot are not subject to critical hits. The Improved Critical feat does not affect these weapons.
Burst weapons rely on confirmed critical hits. If the opponent is not subject to critical hits, burst weapons don't burst.
