These are the core elements of UNO ONLINE. Understanding them is the first step to becoming a master:
- Skip: The next player is eliminated.
- Reverse: Changes the direction of play (from clockwise to counterclockwise).
- Draw Two ($+2): The next player draws two cards and loses their turn.
- Wild: You get to choose the color for the next turn.
- Wild Draw Four ($+4): The most painful blow. You choose the color, and the next player must draw four cards and lose their turn.

Important Note: When you have two cards left in your hand and are about to play one, you MUST press the "Uno" button. In the online version, if you forget to press it and your opponent notices (by pressing the report button), you will be penalized by drawing 2-4 extra cards, depending on the version.