The Setup
Every player starts with seven cards. The rest of the cards are placed in a Deck face down and a space would be designated for the Discard Pile. The top card from the Deck is placed in the Discard Pile, and the game begins!
Gameplay
The game commences in a clockwise direction. Every player views their cards and tries to match the card in the Discard Pile either by the number, color, or the symbol/action. For instance, if the Discard Pile has a red card that is an 8 you have to place either a red card or a card with an 8 on it. You can also play a Wild card (which can alter current color in play). If the player has no matches, they must draw a card from the Deck. If that card can be played, play it. Otherwise keep the card, and the game moves on to the next person in turn. You can also play a Wild card, or a Wild Draw Four card on your turn. At any time during the game, if the Discard Pile becomes depleted and no one has yet won the round, the Discard Pile is shuffle into the Deck. Take note that you can only put down one card at a time; you cannot stack two or more cards together on the same turn. For example, you cannot put down a Draw Two on top of another Draw Two, or Wild Draw Four during the same turn, or put down two Wild Draw Four cards together.
Calling UNO!
The game continues until a player has two cards left with at least 1 playable card. Just before playing the second to last card, the player must click the 'Call UNO!' button. If card was played without clicking the button, the player will be caught by the opponent(s) and must draw two new cards as a penalty.
Special Cards
Scoring
Once a player plays all their cards, that player wins that round and the scoring phase is entered. Score is calculated by keeping a running total of the points each player is caught with at the end of each round. When one player reaches 500 points, the player with the lowest amount of points is the winner. Card values are:
OutSystems UNO! Rule Exclusions
Note than in OutSystems UNO! the Reneging rule (Ability to choose not to play a playable card from your hand. and draw a card from the Deck instead) and the Wild Draw 4 Card Challenge action are not applicable.