You can play this game to challenge yourself and compete with bots in order to be the one who can win the game. Each game is made of "hands" whose main goal is getting rid of all of your cards. The last player who could not get rid of all their cards is the looser of the hand. Once the hand ends, the server will sum all the numbers of each card (i.e., 1 up to 12, regardless colors) and it will display the current scores of the hand and cumulative game scores across the hands. Whether the game is over depends on the cumulative scores of each player and the maximum cumulative configurable limit (which defaults to 100pts). If any player reaches the maximum cumulative scores, the game/match ends immediately and you will see emojis falling to the ground and a fun show of fireworks!!!
When the turn of the current hand is your own, you must to play at least one card matching number or color of the last card played, which is stacked up at the "heap". In case that you have no cards matching the last card played, you must to pick up cards from the deck and play a matching card or pass turn to the next player. You cannot pass turn without playing cards or picking up from the stack, at least one of them, because this is the main rule of the game and no one can break this rule.
Besides the main rule mentioned above it, it's really important to notice that some cards have special behaviors when they are played. Here's the list.
Whenever a player (human or bots) decides to play a "1", the next immediate player in turn will be forced to pick up 4 cards from the deck. In case that the card played is a "2" and not a "1", the penalty is to pick up 2 cards instead of 4 cards. However, the penalty is cumulative so that if one player chooses to play a "1" and the next play another "1", the third player in turn will have to pick up 8 cards from the deck, and so on. As an exception to the rule, if the first of the cards picked up from the deck is either a "1" or a "2", the player can get rid the recent card to avoid pick more cards up from the deck.
By playing one of these cards, you must to play another card matching number or color. Keep in mind that you can chain your cards by playing either another "4" or "7", because of the resulting effect of the main rule applied right here.
The "10" is the color changing card, meaning that you can play one of those cards and select the same color or another one different from the color of the "10". Then you can get rid of one of your cards, regardless the number of the card. The main rule keeps being okay at this point.
If you play an "11", the immediate player in turn is jumped/skipped and the new turn is automatically assigned to the next player active in the hand.
The game has a rotation direction, which rules who is going to be the next player in turn, and it's clockwise by default. By toggling the state of the variable, the rotation direction will be counter-clockwise if it's clockwise and clockwise if it's counter-clockwise.
That's everything that you've got to know to play this game, so have fun ;-)