Guns are now split into two groups. "Normal" weapons and power weapons. Normal weapons include Hand Cannons, Scout Rifles, Pulse Rifles, Auto Rifles, Sidearms, and Submachine Guns. "Normal" weapons are then further split between Kinetic and Energy. Kinetic weapons are just regular old guns. Energy weapons however have element damage (Arc, Solar, Void) and tend to do more damage than kinetic weapons. Both use different ammo. You can carry one Kinetic weapon and one Energy weapon. Thus you can carry two "primary" guns at the same time. Such as a Scout Rifle and a Auto Rifle. Or a Handcannon and a Submachine Gun. Or two sidearms just to screw with people. Then there are power weapons. Which include Rocket Launchers, Grenade Launchers, Sniper Rifles, Fusion Rifles, Shotguns, and Swords. Power weapons are like "heavies" in the sense they are your big high damage weapon, however they are not quite as powerful as D1 heavies and thus get ammo more frequently.