UNO Extreme is similar to the original version of UNO and it adopts many of the same rules. The key difference in UNO Extreme is that each player must draw from an electronic card shooter, which can release a random number of up to 10 cards.
In the UNO Extreme game, every player is dealt seven cards at the start of the game. The remaining cards reside within the electronic card shooter.
To play the game, the dealer takes a card from the electronic card shooter and starts a discard pile. Each player takes turns playing a card that matches the top card on the discard pile in either color or number. If a player has no cards that match the one at the top of the discard pile, then he must draw from the card shooter and add however many cards the shooter releases to his hand.
The object of UNO Extreme is to play all the cards in your hand. When there is only one card remaining, the cardholder has to shout "Uno!" and alert the other players. If another player does this before the cardholder, then the cardholder has to draw from the electronic card holder.
Some of the cards in UNO Extreme differ from the original UNO. For instance, instead of Wild Draw Four being a card, there's the Wild Hit Fire card, which forces a player to draw from the card shooter.
According to HowStuffWorks, a game usually only takes five to 10 minutes to play, but in some cases it can take much longer.