As they say in the Quake 2 manual, it the "big, uhh, freakin' gun". The BFG fires a slow-moving sphere of green plasma, which in turn fires laser beams at any living thing in sight. A direct hit from the sphere is almost certain death, even for a player with full health and a lot of armor, and the lasers do a good deal of damage on their own. A tactic for using the BFG is firing down a long hallway or into a crowded room, where the lasers have many targets, and there is a chance the someone might blunder into the sphere. It is definitely not a weapon for close-quarters use, due to the massive splash damage the plasma sphere deals when it hits. Each shot from the BFG requires a whopping 50 power cells.

Using the BFG is considered excessively cheap by most hardcore gamers. The BFG requires none of the psychotic fast reflexes of the rocket launcher, the finesse and keen vision of the railgun nor the dogged persistence of the shotgun. Overuse makes you a "BFG whore" to the other players on your server.