I added this rule regarding missile weapon (bows, spears and such) hits to the 1d4 critical table, and also changed it so these weapons function like firearms and energy weapons.
I must say that for the first time ever, I am satisfied with the way ranged weapons work. Also I like the idea of making a player say, "I'm cowering this round."
Perhaps I'll insist they whimper.
Cowering: when fired upon with missile weapons*such as arrows, sling stones, or spears, an unsurprised character may hide beneath a large shield and will, in the case of a normal hit, only take normal hit point damage (e.g. 1d6 from an arrow). Critical hits are considered to have pierced the shield and result in a roll on the wound table. Whilst cowering, a character may move 1/4 the Normal rate.
*Not to be confused with firearms or energy Weapons