Understanding the deep rules of Uno Online Free will make you find this game very interesting and impressive. Because in some cases, you can pass the penalty to the next player by using the Uno Stacking Rule. For example, if the previous player used Draw 2 Card or Wild Draw 4 Card, you can avoid drawing more cards by using the same cards. At this time, the next player is forced to draw four or eight cards if he does not have the same cards to match.