Different Ending
To get a different and longer ending movie Halo, beat the game Legendary.
Infinite Grenades:
To get infinite grenades, scorpion, and ghost in multiplayer- Go to the multiplayer screen: go to edit game types: In that menu you will have the option to make up your own game type.
Unlock 2 new guns:
Beat the easiest setting then on the hardest in 3 hours to unlock 2 new guns
Pistol-Whip It Good:
Never underestimate the power of a well-placed melee attack. Smacking someone or something with the butt of your gun is great fun and immensely effective
Get the Drop on the Dropship:
When a drop ship unloads aliens, the next drop ship will hover in the air. If you take your sniper rifle and zoom in on the sides where the doors open, the targeting cursor will turn red. Fire once or twice and the alien will plummet to the ground.
Best Anti-Flood Weapon:
The combat shotgun is the best weapon when you fight the flood. It'll take them down in 1 or 2 shots. Forget the assault rifle or the plasma weapons shotgun is the way to go.
Flash Flood:
When you encounter the race known as the Flood, turn your flashlight on and point it at them. The large one will stop running and jumping so that they are easier to shoot. But, if you raise your gun to reload, turn away from them or take the light off of them in any way, they will resume running around and try to kill you again. Although the creatures infected by the flood stand still when you point the flashlight at them, they may still shoot if they have a gun, so kill them quickly
Secret Cave There is a secret cave on level 5 at the button of the map entrance. It comes out on the side of the enemies, where they are not expecting it.
Credit:
www.xboxgamers.com
More Shotgun shells
Get a shotgun that has 12 shots and zero clips. After you shoot it a couple times, you should beable to reload manually. You can do this about ten to twenty times.
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"Why do you have to quote others when you can quote yourself?" (Quote by me)
Is God willing to prevent evil, but not able? Then he is not omnipotent.
Is he able, but not willing? Then he is malevolent.
Is he both able and willing? Then whence cometh evil?
Is he neither able nor willing? Then why call him God.
You see things, and you say 'why'. But i dream things that never were and i say 'why not'.