The classic UNO card game, the online version. The GOAL of the game is to get rid of all your cards before the opponents. You can play with two, three or four opponents, controlled by the computer.
Enjoy the game!
Instructions:
When it is your turn, try to match the card on the discard pile, either by color, number, symbol. If you can't, you must draw a card from the pile. If it can be played, you can do so in the same round. Otherwise, it's the next player's turn.
If you only have 1 card left, you must press the UNO button, otherwise you have to pick up 2 cards as penalty.
There are also some special cards that let you make special actions.
Full rules here: https://en.wikipedia.org/wiki/Uno_(card_game).