From the publisher:
A critical hit can be a devastating display of force that lets you take victory with a single well placed strike. However, sometimes, a critical hit can be underwhelming, doing nothing but dealing less than double damage. Feats such as Surprise Knockdown, Lightning Arc, and Triumphant Attack go some way to solving this problem, by granting additional effects when you score a critical hit. The critical augmentation feats presented here use those feats as precedent to give a wide variety for ways to make your critical hits more impressive.
The 34 feats presented in this product are spread across heroic, paragon and epic tiers.