Shields and criticals

[Anaximandroz]

In my first life as vanguard. Noticed improved critical bludgeon don't work with shields, WAI?

[Krelar]

Despite the names, the improved critical feats actually apply to specific groups/types of weapons regardless of actual damage type. (So if you have a special quarterstaff that does slashing damage. it still uses improved critical bludgeoning)

Shields are, intentionally, not on any of these lists.