Complete the following achievements to unlock Xbox Live Gamerscore points.

Defeat the Boss in the Maximum Attack G event (M.A.G.).

Go to the Flyer base on the Planet Parum. Once you select it, go through it looking at every item there. You will eventually find a weapon that is a gun. It is basically a monster on rope. It shoots comets but has low accuracy. You can sell it for 32,000 Mesta.