UNSC Weapons:
Rocket Pistol:
As seen in the first trailer, a cross between a magnum and a rocket launcher, its a muzzle-loaded single-shot explosive weapon used by the chief to escape the burning Forward onto Dawn.
Stationary turret:
As seen at the left of this image, it looks like a turret, who knows.
Covenant:
We dont know if the covenant will be at Halo 4, so we have no weapons in here.
Forerunner:
The only three forerunner weapons known to date are:
Sentinel Beam:
A weapon dropped by a Sentinel, it shoots a blue beam at it can overheat quickly.
Automatic-Turret:
A piece of equipment from halo 3 that shoots players automaticaly.
Pulse Beam:
A weapon that fires small burst of beams, used by the enforcers.
Precursor:
We dont know what weapons may precursors have, this image from the las part of the Concept Art trailer show what could be a precursor holding a laser like weapon:
