Bonus videos
     Collect  the  indicated  number  of  Precursor Orbs to unlock the
corresponding video:

Concept Art: 700 Precursor Orbs
E3 2005 Trailer: 600 Precursor Orbs
Game in Construction: 900 Precursor Orbs
Intro Animatic: 800 Precursor Orbs

Jak Mask
     Play the the prison level and go to the second cell block that is
patrolled  by  three  guards.  Sneak behind the guards and follow them
moving  counter-clockwise.  Collect  the key that is hidden behind the
second pillar. Use it to open the first door you see to the northeast.
Smash the picture on the shelf to find the Jak Mask.