Prey

Casino and Cherokee mode:
Finish the game. After, choose "New Game" option from the main menu.
The "Casino Mode" option should be unlocked.
The "Cherokee Mode" option should be unlocked.

Unlock First Concept art gallery:
Finish the game on the normal difficulty level.

Unlock Second Concept art gallery:
Finish the game on the Cherokee difficulty level.

Prey achievements:
Complete the following achievements to award the indicated amount
of Xbox Live Gamerscore points.

Young Blood (10pts) - Complete 50 kills total in death match.
Ultimate Warrior (50pts) - Complete 500 kills total in death match.
Toxic Overlord (10pts) - Complete 25 kills in death match and team death
match using the Acid Sprayer.
There Are Others (20pts) - There are others Finished.
The Old Tribes (25pts) - The old tribes Finished.
The Dark Harvest (30pts) - The Dark harvester Finished.
The Complex (30pts) - The complex Finished.
Ten Ranked Matches (20pts) - Play ten ranked matches.
Team Player (15pts) - Complete 125 kills in team death match.
Team Member (10pts) - Complete 50 kills in team death match.
Team Leader (20pts) - Complete 250 kills in team death match.
Soul Sucker (10pts) - Complete 25 kills in death match and team death
match using the Leech Gun.
Sharpshooter (10pts) - Complete 25 Sniper kills in death match and
team death match.
Second Chances (15pts) - Second chances Finished.
Saviour (65pts) - Finished game on Normal difficulty.
Sacrifices (20pts) - Sacrifices Finished.
Rites of Passage (10pts) - Rites of passage Finished.
Rifle Ranger (10pts) - Complete 25 kills in death match and team death
match using the rifle.
Resolutions (40pts) - Resolutions Finished.
Rank 1 (20pts) - Win a ranked match.
Oath of Vengeance (50pts) - Oath of vengeance Finished.
Mother's Embrace (60pts) - Mother's embrace finished.
Mechanic (10pts) - Complete 25 kills in death match and team death
match using the wrench.
Machine Gun Tommy (10pts) - Complete 25 kills in death match and team
death match using the Auto-Cannon.
Launcher Lord (10pts) - Complete 25 kills in death match and team
death match using the Crawler Launcher.
Last Call (10pts) - Last call complete.
Jen (25pts) - Jen Finished.
Invisable Assassin (10pts) - Complete 25 kills in death match and
team death match using spirit form.
Hidden Agenda (25pts) - Hidden agenda Finished.
Guiding Fires (20pts) - Guiding fires Finished.
Galactic Hero (65pts) - Finished game on Cherokee difficulty.
Following Her (30pts) - Following her Finished
Facing the Enemy (50pts) - Facing the enemy Finished.
Escape Velocity (10pts) - Escape velocity Finished.
Downward Spiral (10pts) - Downward Spiral Finished.
Crawler King (10pts) - Complete 25 kills in death match and team
death match using Crawler grenades.
Crash Landing (15pts) - Crash landing Finished.
Center of Gravity (40pts) - Center of gravity Finished
Brave Star (15pts) - Complete 125 kills in death match.
Ascent (40pts) - Ascent Finished.
All Fall Down (15pts) - All fall down Finished.