The Gunner is a Soldier unit which has the useful ability to spray fire into a three-block wide target area, and up to two rows deep. They are unlocked at Level 8, and are useful for clumped, unarmored enemy formations, such as Raiders and most Critters.
At Rank 3, a new attack option, Heavy Fire, is available for research, which essentially doubles the potential damage output of the Gunner, as it increases the total number of attacks from the initial 3 to 6 potential hits. The primary limiting factor to this attack is the fact that it can only be used twice before the Gunner's ammunition is expended. Besides the extra ammo expenditure and negligible accuracy reduction, the attack has the same cooldown as the normal attack. It is recommended that players spend the Nanopods and research this weapon upgrade.
On their own, Gunners are extremely fragile. They have low defense and only 70 at Rank 1. That means that if the enemy can target them, the Gunner will die quickly. Placing a Gunner in the first row is feasible if the player can afford to lose the Gunner in order to maximize its potential damage. A more conservative play is to play the Gunner in the second row, shielding it somewhat from Direct Line of Fire. As a Piercing damage-type unit, the Gunner will do negligible damage to heavily armored units. Against lighter armored units, such as Riot Troopers, the Gunner can quickly degrade their armor.