It is also similar to the Collector Particle Beam and the enemy Pyro flamethrowers, firing a burst of flame straight ahead. This is a short-range weapon.
The Firestorm is an excellent option for "crowd control." This weapon is extremely effective against swarming, melee-based units such as husks and varren. The weapon's armor damage modifier is also helpful at higher difficulty levels (i.e., Hardcore, Insanity), where many melee units possess armor.
The Firestorm is an excellent weapon for classes without shotgun training since it provides a very potent short range weapon as well as for Soldiers using the Vindicator battle rifle since its constant stream of fire helps compensate for the player's lack of an automatic weapon.
The Firestorm uses power cells much more efficiently than any other heavy weapon and can thus be used far more frequently.
This weapon is good for keeping enemies at bay whilst your health and shields recharge, a burst of flame will cut-out the enemy's shields and make them "dance about" trying to put the fire out for long enough for your health and shields to recharge. This also leaves the enemy vulnerable to a quick headshot.
The Firestorm does not cause any type of damage to Shepard or the squad (if they wander in front of it) regardless of difficulty setting, allowing it to be fired at point blank range safely (one of four heavy weapons capable of this: the M-622 Avalanche, Collector Particle Beam and Arc Projector are the other three).
The Firestorm will burn slowly for a second, then after a second of the trigger being pressed, will burn much faster, for much more damage.
Sometimes picking up another Firestorm while holding one with more ammunition will cause the Firestorm to be replaced with the one containing less ammunition, and the Firestorm with more ammunition will disappear.