Dual-wield
It is possible to increase your firepower by wielding two weapons, however it should be noted that two-handed weapons will incur an (unknown) accuracy penalty, according to Roger Wong's Gamespot Guide. The [Lawpistol], Plasma Gun and Toxigun do not incur any accuracy penalty when dual-wielded. Technically, the launchers incur a penalty, but since missiles are guided they don't make use of the unit's accuracy. Same goes for the power sword too due to its proximity requirements.