Gunner :

• Fire bullets on minigun + volatile bullets on revolver = makeshift flamethrower with high single target dps
• Salvo on the rocket launcher with high rate of fire = rocket shotgun (can go with stun or flame)
• Rocket barrage on rocket launcher

Driller : Disperser compound / goo bomber with goo gun + burning nightmare plasma charger

Scout : Supercooling chamber with the m1000 for bosses

Engi : Nuke