From The TimeSplitters Wiki

Minigun
Ammo	400
Fire Rate bullets per sec/cartridge time	? rpm
Reload Time	Overheating: 2 secs
Damage (per Single Shot) Head/Body/Leg	?
Type	Automatic
Zoom	None
Primary Fire	Fire
Secondary Fire	Barrel spin
Games	TS, TS2, TSFP

The Minigun is an electronic Gatling gun. It dispenses rounds from its six rotating barrels at an incredible rate of fire, although continuous fire will result in the barrel overheating, reducing the firing speed (and effectiveness) of the weapon to about that of a semi-automatic pistol. When the trigger is held down, there is a slight delay before the gun starts firing while the barrel heats up. When the trigger is released, the barrel begins to slow to a stop. The weapon's alternate fire mode keeps the barrels "warmed up" so you can fire immediately. The slight drawback of this secondary mode is that overheating will occur more quickly.

In TimeSplitters 1 the gun is much smaller than other incarnations, and the Minigun can be dual-wielded. In TimeSplitters 2 and TimeSplitters: Future Perfect, the Minigun is much bigger and takes up a bigger portion of the screen.