Clash Royale is a game by Supercell, the makers of the famous game 'Clash of Clans'.
It is a card game and largely uses the player's strategic awareness and elixir management skill. 'Elixir'is a liquid that keeps on generating till its maximum storage of 10 cubes. Each card in the game has a specific elixir requirement.
The player is required to attack the opponent's tower and destroy while making sure that his own tower is defended. The duration of a match is 3 minutes and the player who destroyed the most out of the 3 total towers wins the match. In case of a draw the match goes into extra time to decide the winner, if the extra time also fails to find a winner, the match is declared to be a draw.
Overall it is a good game, a strategic one. Just make sure that you keep watch of the time you spend on it. Have fun guys!