If you ever run out of Light, Dark, or Anihilator Beam Ammunition when you need it to open a door or something, here is some help. Instead of going back and finding an enemy to destroy, select the beam, charge it up with the "A" and release. The beam will be fired reguardless if it has no ammunition, however, do not expect to be able to use this blast to destroy an enemy because the beam will be extremely weak.