Ahhhh my young n00b , that's just the sounds of the greatest games in the world. All neo carts rattle a little(even neo pocket games) it's completely normal. Weclome, btw. If you have any more q's don't be afraid to ask. What other games do you have??
Actually, I own The Last Blade and a friend of mine also has a jpn copy as well. Neither of our Last Blade carts rattle a bit. This is the only Game I'm aware of that doesn't seem to rattle.