This unknown weapon is the main weapon used by the alien forces. It has 6 barrels and a grenade laucher attachment. It fires low calibre incendary type rounds of an unknown material.
The aliens' weapon fires incendary rounds of an unknown type. These rounds appear to be contained in a caseless magazine and reload atomaticaly through an implant on the wrist.
The grenade launcher fires some kind of explosive; either rockets or charges of white phosphorus. These are different to human grenades as proven near the end of the film where a puzzled alien picks up a frag grenade and looks at it before being blown up.
The extraterrestrial weapon generally lacks power. This is proven as it cannot seem to penetrate the metal of a standard car. The rounds also seem to lack the power to punch through body armour except on a direct hit. This is made up for by the fact that the weapons cause burns as well as standard ballistic injuries.
The grenade launchers seem to be very powerful as they are seen to destroy a M1A2 Abrams in 1-2 hits (although to be fair to the M1A2 Abrams, the grenades simply put the tank out of action by destroying the engine) aswell as destroy walls and other obstickles very quickly.