Launch trailer: 'Pokemon Rumble World'

Nintendo's "Pokemon Rumble World,"a free-to-play game for the 3DS, releases on April 8, heralded by a launch trailer.

Nintendo's 'Pokemon Rumble World,'a free-to-play game for the 3DS, releases on April 8, heralded by a launch trailer.

The Pokemon spin-off for 3DS is the fourth in the 'Rumble' series.

The downloadable game allows you to collect 719 species of Pokemon and, while free to play, involves in-game microtransactions -- namely, the buying of Poke Diamonds.