Card games are such a natural fit for iPhone. Uno is no exception, with intuitive touchscreen controls and pleasant presentation. Multiplayer, however, serves up a wild card that transforms this classic card game from blue to red hot.

If you're an Uno initiate, the colour-coded card game is easier than ever to learn. The goal is simple: get rid of all your cards. You do this by taking turns with your competitors, placing cards on top of a central pile. In order to play a card, it must be the same color or number as the card currently on top of the pile. Alternatively, wild cards can be set down any time. Once you've whittled down your hand to a single card, a tap of the 'Uno' button is needed to let everyone know you're one away from winning.

Since you're not physically holding a deck of cards, Uno allows you to line up your digital deck along the bottom of the screen (when held in landscape mode) with the pile situated in the centre. Tapping on your cards fans them out and you can either double tap to put one in play or slide it onto the pile. Responsiveness is an issue here, with cards moving a split-second after you've slid your finger or double-tapped. On some occasions it can result in the wrong card being plunked down, but rarely is it crippling. Annoying, yes, but not serious enough to be a game breaker.

While the game does feature solo play, it's mulitplayer that gives the game colour. Uno lets you play with up to three friends in a trio of multiplayer modes: hot seat, local wireless, and online. Passing around your handset for a game works well given the game's turn-based play, as does local wireless matches. Of course, a paper deck of Uno would be preferrable to these local games but it's a nice option nonetheless.

Online is really where Uno shows its hand. Connecting via wi-fi, you can jump into games with up to three other players. Wins contribute to an overall numerical ranking and you can see how you stack up on a general leaderboard. Customisable player icons also help you stand out online, although unlocking these requires getting through the single player game. Bonus backgrounds and other goodies can also be unlocked and then used to tailor the games you host online.

Flush with features and as colourful as a rainbow, Uno deals a decent hand. The controls need tuning and the single player is somewhat of a side show, but multiplayer acts as a surprising wild card that makes the game a worthwhile draw.