How to get unlockables:
Riddick Prototype #1 + Riddick Combo Trailer: in the Dream find Hogdahl's Finest
Riddick Prototype #3 + Movie Prop 1: in the Guard Quarters find Gronkos bar
Riddick Movie Teaser + Riddick First playable 1: in the Feed Ward find Sensai
Cigarette List: in the Take Off Platform find Space Cowboy
Movie Still #1: in the Dream Find Desert Air