There are a wide variety of weapons in 3079, which can be used by either the player or another NPC. All ranged weapons use a certain amount of energy, which when depleted will cause a "life support brownout" and remove a small amount of health - however, when this happens there's also a chance to increase your total energy capacity.
Blasters: A fast weapon that is good at short to medium range, uses a small amount of energy, and can be fired very quickly. This is a good first weapon to have, as it can take down low-level enemies quickly.
Assault rifles: Fires a multi-round burst, good at medium range. Uses a medum amount of energy. This is a good all-around weapon.
Shotguns: Fires many projectiles at once, a great close range weapon. Uses medium energy.
Heavy guns: Fires a single, relatively slow projectile, somewhat similar to a rocket launcher. The shot explodes on impact, and can destroy soft terrain. Useful at medium to long range, and take medium energy to use.
Precision rifles: A powerful and very accurate rifle, great for sneak-attacks and sniping from cover. Uses medium to high energy, secondary action is a scoped zoom.
Launchers: Fires one to three grenades that bounce and explode, can deal a great damage but uses a large amount of energy. These grenades can also deform terrain, allowing for the quick creation of traps or trenches, as well as the ability to halt an oncoming enemy by dumping it into a quickly created pit while simultaneously doing a good deal of damage to it.
Knives & Swords: Used for close range attacks that deal great damage and use no energy.
Demon Smiters: A special class of weapon (so far mainly swords), which is the only type of weapon that can do damage to the red translucent demons that you will encounter in later stages of the game. If your Demon smiter is a lower level than the actual Demon it self, it will not one-hit the Demon, if it is above the level of a Demon, it will always 1-hit it.