When there is DRAW2 towards you, you may place another DRAW2 of any color. The cards go on to the person following you. Every DRAW2 adds 2 to the total that must be drawn.
When there is DRAW2 towards you, you may place SKIP of the same color. The cards go on to the person following you. SKIPs used this way add 1 card to the total that must be drawn. You may play a SKIP on any color SKIP in the same way, when there are points at stake.
When there is DRAW2 towards you, you may place REVERSE of the same color. The person following you now must draw for both, or pass it on. REVERSEs used this way add 1 card to the total that must be drawn. You may play a REVERSE on any color REVERSE in the same way, when there are points at stake.
When you are skipped, you may choose to play a SKIP. Then the person following you is skipped instead, and the SKIP counts as your turn. I call this 'en passent', as in chess.
This is the most challenging rule of power Uno. You may play a card at any time during the game, if it matches the card on the top of the stack. If there are cards waiting to be drawn, they go to the person immediately following you. Otherwise, it simply becomes their turn and gameplay continues.
NOTE: When there is a DRAW4 towards you, you can match it and the person following you must draw all the cards. However, if the person following you plays before you can match, you have no choice but to draw the cards. They do not need to wait.
If someone has one card and does not call uno, you may say, "forgot to say uno" and thaty person must pickup 7 extra cards. However, if they play that last card, they are out and no longer need to say uno.
If someone has no cards they are out, the hand is over unless there are still cards needing to be picked, or someone can match the top card.
If there are cards needing to be picked up, players can continue to use the above rules until someone is forced to pick them up.
If someone can match the top card, they may do so to get rid of points.
If either of these effects causes the person with no cards to pickup cards, then the hand is not over and play continues.
Once someone wins, points are as follows:
Number cards -- value on the card
SKIP, DRAW2, REVERSE -- 20 points
MIRROR -- 30 points
WILD -- 50 points
DRAW4 -- 100 points
There are two way to keep score.
GOOD POINTS: when someone wins a hand they receive the total points from everyone at the table. First one to 1000 wins. (or play to 5000, takes more than one day)
BAD POINTS: when someone wins a hand everyone receives the points in their hand. Lowest score when someone reaches 1000 wins. (or play to 5000, takes more than one day)
I recommend good points as there is more of an advantage to winning hands.
If you make an error such as playing out of turn or playing an invalid card, another player may call stupid warning on you. If you make a mistake after receiving the stupid warning, another player may invoke the stupid rule and you must draw 3 cards.
This rule is to discourage lunacy, and should be used only when absolutely necesary to bring a rebel player into line. Not intended for use on new players or in situations where gameplay was genuinely confusing, or when it has a direct effect on game outcome (ie. on a person with uno.)
In some Uno decks there are blank cards, or rule cards. These are called MIRROR cards, and take on the properties of any card they are played on. A MIRROR on a DRAW4 becomes a DRAW4. A mirror on a DRAW2 becomes a DRAW2. A mirror on a yellow 3 becomes a yellow 3, etc.
Limitation on MIRROR cards: A MIRROR card may only be matched to an identical mirror card when using the matching rule, so they can only rarely be played out of turn.