|Release: 2009 (Japan) - Capcom|
All images via the official site.
Here's how it works...
The start and primary portion of the game is a digital slot machine. You play by popping in tokens and hoping you get lucky by stopping the slots on something good. Depending on what you get, you could win a few more tokens in-game, trigger an enemy and/or power-up to appear in a minor event, or start a full-fledged minigame.
Once you get past the luck of the slots, most (but not all) of the minigames are based on skill and tricky timing. Don't expect the fluid controls of a normal Mario game with the unwieldy arcade joystick though; these games tend to give you only limited control over Mario, for example, only controlling his jumps, moving platforms up and down, or shooting fireballs. As pictured above, some of the minigames can be played with up to three other players, and their actions may affect how the game plays out on your part of the screen.
|"Mario Satellite - Mario Jackpot Challenge"|
The ultimate goal of the game is enter "Jackpot Step Challenges" by getting lucky on the slots. These challenges are minigames with the opportunity to collect keys. If you're able to collect five of either the Mario keys or Peach keys, you can enter the Jackpot Challenge. This is a battle against Bowser, which seems to be basically just mashing the fireball button and hoping the giant roulette wheel in the center lands on the jackpot.
|Another simple timing-based minigame|
Presumably, if you're able to beat the odds and have enough skill when it counts, you'll be able to keep your game going long enough with real life tokens and in-game tokens to net one of the two jackpots, maybe even getting you a big enough payout of tokens to make the investment worth it.
And that's about all there is to New Super Mario Bros. Wii Coin World. For more images and videos, check out the official website or search on Youtube for "New スーパーマリオブラザーズ Wii コインワールド".
For more Mario stuff that's only in Japan, check out Super Mario Bros. Special, the terrible PC version of Super Mario Bros..