Following a delay earlier this year, Metroid Prime: Federation Force is finally set to launch next month (or two months from now if you live in Europe or Australia), and Nintendo is giving players a taste of the game early. Federation Force will be bundled with a side game called Blast Ball in which two teams of three Marines compete in a game of soccer while wearing mech suits.
Federation Force‘s release, Nintendo has made Blast Ball free to download on the Nintendo 3DS eShop. This is being labeled as a special demo, and the online servers will apparently only be supported for a limited time. Full online play will be available again when Federation Force releases in full.
Source: Nintendo Everything