There were three challenge packs released, two character packs and console themes.
All the Trappings Challenge Pack 1
Things that Go Boom Challenge Pack 2
A Hazardous Reunion Challenge Pack 3
These character packs don't change much in terms of gameplay but cutscenes are different.
Kane and Lynch Character Pack
Raziel and Kain Character Pack
Images are from Steam and the Square Enix North America Store