You can't add weapons to the game. You can change existing ones, but not add them. And if you change an existing one, then the race that uses the existing one will look strange. I encountered this problem with Sci-fi Bashfest- do I call Pulse Phasers Turbolasers and make them red, or leave the name pulse phasers and leave them yellow? I finally decided to leave them Pulse Phasers- it still looks pretty cool.