Find a dart anywhere in any level. Next, find the highest rocky mountain that you cannot climb up. Take your dart up that mountain/slope. Before you go up, look all the way up and keep looking in that direction. When you get to the top of the mountain, keep holding Forward and looking up. The dart will move into the sky. Do not release it yet. Keep going into the sky. You will fall off, but keep looking up all the way and watch the dart. It will fly quickly into the sky and disappear. Note: This glitch will not allow you to stay flying. Note: This works best with custom maps.
From the main menu, go to settings, cheatcodes, and enter the code.

Legend: L=Left on D-pad LT = Left Trigger X = X

L, LT, X, L - Gamestop Multiplayer Level
Fire Accelerator - Increases fire rate
Recoil Stabiliser - Increases accuracy
Armor-piercing - Increases damage
Servo-Reloader - Increase reload speed
Magneto Concentrator - Creates a laser mine at close range
Titanium Concentrators - Creates a stronger mine at close range
Remote Detonator - Increases ammo to 8; allows for manual trigger
Fragment Attraction - Increases blast size and ammo to 10
Target Leech - Increases ammo to 12
Fast Injector - Faster doses mean faster health restore
Health Boost - Adds one life point
Adrenal Boost - Adds one more life point
Arc Sphere - Charge weapon to unleash damage orb
Defense Sphere - Damage orb endures longer and explodes on contact
Explosive Sphere - Damage orb endures longest; explosion is larger
Heat-Seeking - Warhead heat-seeks after holding trigger and firing
Dual Warheads - Two warheads fired
Quad Warheads - Four warheads fired
Enhanced Vision - Highlights enemies in scope view
Increased Ammunition - Increases ammo to 6 in magazine, 18 reserve
Armor-piercing - Increases damage